Journal articles: 'Chloro Position'

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A., RAMESH, SYAMA SUNDAR B., and S. RADHAKRISHNA MURTI P. "Kinetics of Substitution of 2,4,6-Trichlorofyrimidine Enhanced Reactivity of 2-Chloro Position." Journal of Indian Chemical Society Vol. 72, Jun 1995 (1995): 413–15. https://doi.org/10.5281/zenodo.5905003.

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Department of Chemistry, Nagarjuna University, Nagarjunanagar-522 510 Manuscript received 24 August 1993, accepted 14 December 1993 Kinetics of Substitution of 2,4,6-Trichlorofyrimidine Enhanced Reactivity of 2-Chloro Position

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Rajam, Ammaiyappan, Packianathan Thomas Muthiah, Raymond John Butcher, Jerry P. Jasinski, and Jan Wikaira. "Design of two series of 1:1 cocrystals involving 4-amino-5-chloro-2,6-dimethylpyrimidine and carboxylic acids." Acta Crystallographica Section C Structural Chemistry 74, no. 9 (2018): 1007–19. http://dx.doi.org/10.1107/s2053229618009154.

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Two series of a total of ten cocrystals involving 4-amino-5-chloro-2,6-dimethylpyrimidine with various carboxylic acids have been prepared and characterized by single-crystal X-ray diffraction. The pyrimidine unit used for the cocrystals offers two ring N atoms (positions N1 and N3) as proton-accepting sites. Depending upon the site of protonation, two types of cations are possible [Rajam et al. (2017). Acta Cryst. C73, 862–868]. In a parallel arrangement, two series of cocrystals are possible depending upon the hydrogen bonding of the carboxyl group with position N1 or N3. In one series of cocrystals, i.e. 4-amino-5-chloro-2,6-dimethylpyrimidine–3-bromothiophene-2-carboxylic acid (1/1), 1, 4-amino-5-chloro-2,6-dimethylpyrimidine–5-chlorothiophene-2-carboxylic acid (1/1), 2, 4-amino-5-chloro-2,6-dimethylpyrimidine–2,4-dichlorobenzoic acid (1/1), 3, and 4-amino-5-chloro-2,6-dimethylpyrimidine–2-aminobenzoic acid (1/1), 4, the carboxyl hydroxy group (–OH) is hydrogen bonded to position N1 (O—H...N1) of the corresponding pyrimidine unit (single point supramolecular synthon). The inversion-related stacked pyrimidines are doubly bridged by the carboxyl groups via N—H...O and O—H...N hydrogen bonds to form a large cage-like tetrameric unit with an R 4 2(20) graph-set ring motif. These tetrameric units are further connected via base pairing through a pair of N—H...N hydrogen bonds, generating R 2 2(8) motifs (supramolecular homosynthon). In the other series of cocrystals, i.e. 4-amino-5-chloro-2,6-dimethylpyrimidine–5-methylthiophene-2-carboxylic acid (1/1), 5, 4-amino-5-chloro-2,6-dimethylpyrimidine–benzoic acid (1/1), 6, 4-amino-5-chloro-2,6-dimethylpyrimidine–2-methylbenzoic acid (1/1), 7, 4-amino-5-chloro-2,6-dimethylpyrimidine–3-methylbenzoic acid (1/1), 8, 4-amino-5-chloro-2,6-dimethylpyrimidine–4-methylbenzoic acid (1/1), 9, and 4-amino-5-chloro-2,6-dimethylpyrimidine–4-aminobenzoic acid (1/1), 10, the carboxyl group interacts with position N3 and the adjacent 4-amino group of the corresponding pyrimidine ring via O—H...N and N—H...O hydrogen bonds to generate the robust R 2 2(8) supramolecular heterosynthon. These heterosynthons are further connected by N—H...N hydrogen-bond interactions in a linear fashion to form a chain-like arrangement. In cocrystal 1, a Br...Br halogen bond is present, in cocrystals 2 and 3, Cl...Cl halogen bonds are present, and in cocrystals 5, 6 and 7, Cl...O halogen bonds are present. In all of the ten cocrystals, π–π stacking interactions are observed.

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Hayashi, Norihiro, Yoshihiro Nakata, and Akira Yazaki. "New Findings on the Structure-Phototoxicity Relationship and Photostability of Fluoroquinolones with Various Substituents at Position 1." Antimicrobial Agents and Chemotherapy 48, no. 3 (2004): 799–803. http://dx.doi.org/10.1128/aac.48.3.799-803.2004.

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ABSTRACT The present study examined the phototoxicities of a series of 7-(3-aminopyrrolidinyl) quinolones containing various substituents at position 1 (in which the substituent at R8 is a hydrogen or a halogen) by use of a mouse model. For the 7-(3-aminopyrrolidinyl) quinolones with a halogen atom at position 8, well-known substituent groups such as a cyclopropyl, an ethyl, or a difluorophenyl at position 1 were found to be responsible for severe phototoxicity. However, when an aminodifluorophenyl or an isoxazolyl group was placed at position 1, even 8-halogeno quinolones were found to be mildly phototoxic. This is the first report of 8-halogeno quinolones that are not severely phototoxic. Two structurally similar 8-chloro quinolones (the 1-aminodifluorophenyl 8-chloro quinolone and the 1-difluorophenyl 8-chloro quinolone) were investigated further. The former was mildly phototoxic; the latter was severely phototoxic. We demonstrate that these two 8-chloro quinolones have practically the same areas under the concentration-time curves from 0 to 4 h in auricular tissue, suggesting that the mild phototoxicity is not due to pharmacokinetic instability. The rates of UV photodegradation of these compounds were also measured. We found that these two quinolones photodegrade at similar rates, suggesting that the mild phototoxicity is not attained through increased photostability. In conclusion, the phototoxic potentials of fluoroquinolones are influenced not only by the substituent at position 8 but also by that at position 1 (a new finding from this study). We also discovered a mildly phototoxic 8-chloro quinolone which did not have increased photostability.

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4

Cherubim, P., and LW Deady. "Nucleophilic Substitution Reactions in Benzo[C][1,8]naphthyridines. II." Australian Journal of Chemistry 43, no. 8 (1990): 1469. http://dx.doi.org/10.1071/ch9901469.

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3-Chloro-1-methyl-6-(p- methylphenoxy ) benzo [c][1,8] naphthyridine has been prepared, the reactions with various nitrogen, oxygen and sulfur nucleophiles studied, and the results compared with those for the 1- chloro-3-methyl isomer. The 6-position was more reactive for oxygen and nitrogen nucleophiles, so much so that an initially added 6-NHR group was displaced by a second R′NH2 nucleophile at least as readily as was the 3-chloro group. With p- chloro ( thiophenol ), however, the 3-chloro group was preferentially displaced.

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Deady, LW, and DM Werden. "Nucleophilic-Substitution Reactions in Benzo[C][1,8]Naphthyridines." Australian Journal of Chemistry 39, no. 4 (1986): 667. http://dx.doi.org/10.1071/ch9860667.

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The reactions of 1-chloro-3-methyl-6-(p- methylphenoxy ) benzo [c][1,8] naphthyridine with a variety of nucleophiles are reported. The relative reactivity of the 1- and 6-positions depends on the nucleophile and reaction conditions. Anilines, and alkyl and aryl thioxides react at position 1, alkylamines and alkoxide at position 6, and acidified alcohol at both 1 and 6. Some possible reasons for these positional reactivities are discussed.

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6

Birzan, Liviu, Mihaela Cristea, Constantin Draghici, Victorita Tecuceanu, Maria Maganu, and Alexandru C. Razus. "4-(azulen-1-yl)-2,6-diphenylchalcogenopyrylium Perchlorates; Synthesis and Characterization." Revista de Chimie 71, no. 6 (2020): 89–95. http://dx.doi.org/10.37358/rc.20.6.8174.

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2,6-Diphenyl substituted thio- and seleno-pyrylium salts with azulen-1-yl moieties in 4-position were prepared from phenylacetylene going through chalcogenopyrones and 4-chloro-chalcogenopyrylium salts as intermediates. The final step of synthesis involves the electrophile substitution in 1-position of azulenes with the obtained chloro-derivatives and the products isolation as stable perchlorates. The electronic and magnetic spectra of products are presented and compared with those of the corresponding pyrylium salts.

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7

Bzowska, A., Z. Kazimierczuk, and F. Seela. "7-Deazapurine 2'-deoxyribofuranosides are noncleavable competitive inhibitors of Escherichia coli purine nucleoside phosphorylase (PNP)." Acta Biochimica Polonica 45, no. 3 (1998): 755–68. http://dx.doi.org/10.18388/abp.1998_4269.

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A series of 7-deazapurine 2'-deoxyribofuranosides were synthesized according to already known procedures and their substrate and inhibitor properties with purified E. coli purine nucleoside phosphorylase were examined. In agreement with previous findings, substrate activity was not detected for any of the compounds tested. Most of the nucleosides showed weak inhibition in the preliminary screening, i.e. at a concentration of about 100 microM. However some combinations of 6-chloro, 6-amino or 6-methoxy substituents with bulky hydrophobic groups at position 7 of the base and/or chloro, amino, methoxy or methylthio group at position 2 markedly enhanced affinity of such modified nucleosides for the E. coli enzyme. The most potent inhibition was observed for two nucleosides: 6-chloro- and 2-amino-6-chloro-7-deazapurine 2'-deoxyribofuranosides that show inhibition constants Ki = 2.4 and 2.3 microM, respectively. Several other compounds were also found to be good inhibitors, with inhibition constants in the range 5-50 microM. In all instances the inhibition was competitive vs. the nucleoside substrate 7-methylguanosine. Inhibition constants for 7-deazapurine nucleosides are in general several-fold lower than those observed for their purine counterparts. Therefore 7-deaza modification together with substitutions at positions 2, 6 and 7 of the base is a very promising approach to obtain competitive noncleavable inhibitors of E. coli PNP that may bind to the enzyme with inhibition constants in the microM range.

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8

Hfaiedh, Anoir, Hamed Ben Ammar, Jean-François Soulé, and Henri Doucet. "Palladium-catalyzed regioselective C–H bond arylations at the C3 position of ortho-substituted fluorobenzenes." Organic & Biomolecular Chemistry 15, no. 35 (2017): 7447–55. http://dx.doi.org/10.1039/c7ob01689a.

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We report herein the palladium-catalyzed C–H bond arylation of fluorobenzene derivatives at the ortho-position to the fluorine atom. Bromo, chloro or methoxy substituents at the fluorobenzenyl ortho-position can be used to increase the reactivity of the C–H bond at the C3 position.

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9

Matsunami, Asuka, Shigeki Kuwata, and Yoshihito Kayaki. "Regioselective Transfer Hydrogenative Defluorination of Polyfluoroarenes Catalyzed by Bifunctional Azairidacycle." Organics 3, no. 3 (2022): 150–60. http://dx.doi.org/10.3390/org3030012.

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The catalytic hydrodefluorination (HDF) with a bifunctional azairidacycle using HCOOK was examined for cyano- and chloro-substituted fluoroarenes, including penta- and tetrafluorobenzonitriles, tetrafluoroterephthalonitrile, tetrafluorophthalonitrile, 3-chloro-2,4,5,6-tetrafluoropyridine, and 4-cyano-2,3,5,6-tetrafluoropyridine. The reaction was performed in the presence of a controlled amount of HCOOK with a substrate/catalyst ratio (S/C) of 100 in a 1:1 mixture of 1,2-dimethoxyethane (DME) and H2O at an ambient temperature of 30 °C to obtain partially fluorinated compounds with satisfactory regioselectivities. The C–F bond cleavage proceeded favorably at the para position of substituents other than fluorine, which is in consonance with the nucleophilic aromatic substitution mechanism. In the HDF of tetrafluoroterephthalonitrile and 4-cyano-2,3,5,6-tetrafluoropyridine, which do not contain a fluorine atom at the para position of the cyano group, the double defluorination occurred solely at the 2- and 5-positions, as confirmed by X-ray crystallography. The HDF of 3-chloro-2,4,5,6-tetrafluoropyridine gave preference to the C–F bond cleavage over the C–Cl bond cleavage, unlike the dehalogenation pathway via electron-transfer radical anion fragmentation. In addition, new azairidacycles with an electron-donating methoxy substituent on the C–N chelating ligand were synthesized and served as a catalyst precursor (0.2 mol%) for the transfer hydrogenative defluorination of pentafluoropyridine, leading to 2,3,5,6-tetrafluoropyridine with up to a turnover number (TON) of 418.

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10

Pham, Em Canh, Tuong Vi Thi Le, and Tuyen Ngoc Truong. "Design, synthesis, bio-evaluation, and in silico studies of some N-substituted 6-(chloro/nitro)-1H-benzimidazole derivatives as antimicrobial and anticancer agents." RSC Advances 12, no. 33 (2022): 21621–46. http://dx.doi.org/10.1039/d2ra03491c.

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The purpose of this study is to synthesize novel N-substituted 6-(chloro/nitro)-1H-benzimidazole derivatives with various substituted aryl groups at position 2 and alkylation at position 1, and evaluate their antimicrobial and anticancer activities.

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11

Abdel-Hay, Karim M., Tarek S. Belal, Younis Abiedalla, et al. "Gas Chromatography–Mass Spectrometry (GC–MS) and Gas Chromatography–Infrared (GC–IR) Analyses of the Chloro-1-n-pentyl-3-(1-naphthoyl)-Indoles: Regioisomeric Cannabinoids." Applied Spectroscopy 73, no. 4 (2018): 433–43. http://dx.doi.org/10.1177/0003702818809998.

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The analytical differentiation of the indole ring regioisomeric chloro-1- n-pentyl-3-(1-naphthoyl)-indoles is described in this report. The regioisomeric chloroindole precursor compounds, N- n-pentyl chloroindole synthetic intermediates, and the target chloro-substituted naphthoylindoles showed the equivalent gas chromatographic elution order based on the position of chlorine substitution on the indole ring. The regioisomeric chloro-1- n-pentyl-3-(1-naphthoyl)-indoles yield electron ionization mass spectra having equivalent major fragments resulting from cleavage of the groups attached to the central indole nucleus. Fragment ions occur at m/z 127 and 155 for the naphthyl and naphthoyl cations common to all indoles having the naphthoyl group substituted at the indole-3 position. Fragments resulting from the loss of the naphthoyl and/or n-pentyl groups from the molecular radical cation yield the cations at m/z 318, 304, 248, and 178. The characteristic (M–17)+ fragment ion at m/z 358 resulting from the loss of OH radical is significant in the mass spectra of all these compounds with 1-naphthoyl groups substituted at the indole-3 position. The vapor phase infrared spectra provide a number of characteristic absorption bands to identify the individual isomers.

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12

Meijboom, Reinout, Alfred Muller та Andreas Roodt. "Di-μ2-chloro-bis[(benzyldiphenylphosphine)chloropalladium(II)]". Acta Crystallographica Section E Structure Reports Online 62, № 4 (2006): m897—m899. http://dx.doi.org/10.1107/s1600536806010580.

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The molecule of the title compound, [Pd2Cl4(C19H17P)2] or [Pd(μ2-Cl)Cl(PPh2Bz)]2, where Bz = CH2Ph, lies on an inversion centre. The Pd atom has a distorted square-planar coordination environment formed by a benzyldiphenylphosphine [Pd—P = 2.2218 (6) Å], a terminal chloride [Pd—Cl = 2.2729 (5) Å] and two bridging chloride ligands. The Pd—Cl bond in the position trans to the phosphine ligand [Pd—Cl = 2.4123 (5) Å] is considerably longer than the Pd—Cl bond in the position trans to the terminal chloride [Pd—Cl = 2.3155 (5) Å].

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13

Mekheimer, Ramadan A., Mariam A. Al-Sheikh, Hanadi Y. Medrasi, Ghayah A. Bahatheg, and Kamal U. Sadek. "Chloroquinoline-3-carbonitriles: Synthesis and Reactions." Current Organic Chemistry 23, no. 7 (2019): 823–51. http://dx.doi.org/10.2174/1385272823666190516120946.

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We herein describe the first review which aims to focus soberly the various synthetic methods and chemical reactions of chloroquinoline-3-carbonitrile derivatives. The reactions are subdivided into groups that cover reactions of chloro substituent at 2 or 4 and 2,4 positions, as well as cyano substituent at 3 position and reactions which involve both groups. Most types of reactions have been successfully applied and used in the production of biologically active compounds.

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14

Krečmerová, Marcela, Antonín Holý, and Milena Masojídková. "Synthesis of 3-(4-Pyridinyl)-, 3-(2-Chloro-4-pyridinyl)- and 3-(2-Amino-4-pyridinyl)propoxymethanephosphonic Acid." Collection of Czechoslovak Chemical Communications 60, no. 4 (1995): 670–80. http://dx.doi.org/10.1135/cccc19950670.

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Reaction of sodium salt of 4-(3-hydroxypropyl)pyridine (I) with diisopropyl p-toluenesulfonyloxymethanephosphonate (II) afforded diisopropyl ester of the corresponding phosphonomethyl derivative (III), together with 4-cyclopropylpyridine (IV). The ester III was converted into free 3-(4-pyridinyl)propoxymethanephosphonic acid (V). The synthesis of 3-(2-amino-4-pyridinyl)propoxymethanephosphonic acid (XVI) started from 4-(3-benzoyloxypropyl)pyridine (VII) via the N-oxide VIII which on heating with phosphoryl chloride afforded the 2-chloro derivative IX. Compound IX was debenzoylated with sodium methoxide to give 2-chloro-4-(3-hydroxypropyl)pyridine (XI). Condensation of sodium salt of XI with tosylate II afforded diisopropyl 3-(2-chloro-4-pyridinyl)propoxymethanephosphonate (XIII) and 2-chloro-4-cyclopropylpyridine (XIV). Deprotection of the ester groups in XIII with bromotrimethylsilane gave 3-(2-chloro-4-pyridinyl)propoxymethanephosphonic acid (XV). The chlorine atom in position 2 was replaced by reaction of compound XV with aqueous ammonia at 200 °C under catalysis with copper(II) sulfate. This gave 3-(2-amino-4-pyridinyl)propoxymethanephosphonic acid (XVI) as the final product.

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15

Nauš, Petr, Pavla Perlíková, Radek Pohl, and Michal Hocek. "Sugar-modified derivatives of cytostatic 6-(het)aryl-7-deazapurine nucleosides: 2′-C-methylribonucleosides, arabinonucleosides and 2′-deoxy-2′-fluoroarabinonucleosides." Collection of Czechoslovak Chemical Communications 76, no. 8 (2011): 957–88. http://dx.doi.org/10.1135/cccc2011082.

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A series of novel sugar-modified derivatives of cytostatic 6-hetaryl-7-deazapurine ribonucleosides: 2′-C-methylribonucleosides, arabinonucleosides and 2′-deoxy-2′-fluoroarabinonucleosides bearing an alkyl, aryl and hetaryl group in position 6 were prepared by palladium catalyzed cross-coupling reactions of corresponding (protected) 6-chloro-(7-fluoro)-7-deazapurine nucleosides with (het)arylboronic, hetarylstannanes and trimethylaluminium eventually followed by deprotection. Key intermediate 6-chloro-7-deazapurine 2′-C-methyl-β-D-ribofuranoside was prepared via a stereoselective nucleobase anion glycosylation with toluoyl-protected 1,2-anhydro-2-C-methylribofuranose. The 1,2-anhydro sugar was synthesized in 3 steps starting from readily available 2-C-methylribonolactone. The 6-chloro-7-deazapurine arabinofuranoside intermediate was obtained by epimerization from 3′,5′-protected 6-chloro-7-deazapurine ribofuranoside via 2′-hydroxyl oxidation followed by reduction. None of the prepared compounds showed any considerable cytostatic or antiviral activity.

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16

Dang, Jeremy D., David S. Josey, Alan J. Lough, et al. "The mixed alloyed chemical composition of chloro-(chloro)n-boron subnaphthalocyanines dictates their physical properties and performance in organic photovoltaic devices." Journal of Materials Chemistry A 4, no. 24 (2016): 9566–77. http://dx.doi.org/10.1039/c6ta02457b.

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We have determined that chloro-boron subnaphthalocyanine (Cl-BsubNc) is a mixture of products with random amounts of chlorination in the bay position. We have developed chemical processes to varying the amount of chlorination.

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17

Goreshnik, Evgeny, Dieter Schollmeier та Marian Mys'kiv. "Influence of Cl/Br substitution on the stereochemical peculiarities of copper(I) π-complexes with the 1-allyl-2-aminopyridinium cation". Acta Crystallographica Section C Crystal Structure Communications 59, № 11 (2003): m478—m481. http://dx.doi.org/10.1107/s0108270103021978.

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By using alternating-current electrochemical synthesis, crystals of the CuI π-complexes bis(1-allyl-2-aminopyridinium) di-μ-chloro-bis[chlorocopper(I)], (C8H11N2)2[Cu2Cl4] or [H2NC5H4NC3H5][CuCl2], and bis(1-allyl-2-aminopyridinium) di-μ-(chloro/bromo)-bis[(chloro/bromo)copper(I)], (C8H11N2)2[Cu2Br2.2Cl1.8] or [H2NC5H4NC3H5][CuBr1.10Cl0.90], have been obtained and structurally investigated. In each of the isostructural (isomorphous) compounds, the distorted tetrahedral Cu environment involves three halide atoms and the C=C bond of the ligand. Both compounds reside on inversion centres, and the dimeric [Cu2 X 4·2H2NC5H4NC3H5] units are bonded into a three-dimensional structure by N—H...X hydrogen bonds. The Br content in the terminal X1 position is much higher than that in the bridged X2 site.

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18

Buzun, Kamila, Anna Kryshchyshyn-Dylevych, Julia Senkiv, et al. "Synthesis and Anticancer Activity Evaluation of 5-[2-Chloro-3-(4-nitrophenyl)-2-propenylidene]-4-thiazolidinones." Molecules 26, no. 10 (2021): 3057. http://dx.doi.org/10.3390/molecules26103057.

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A series of novel 5-[(Z,2Z)-2-chloro-3-(4-nitrophenyl)-2-propenylidene]-thiazolidinones (Ciminalum–thiazolidinone hybrid molecules) have been synthesized. Anticancer activity screening toward the NCI60 cell lines panel, gastric cancer (AGS), human colon cancer (DLD-1), and breast cancer (MCF-7 and MDA-MB-231) cell lines allowed the identification of 3-{5-[(Z,2Z)-2-chloro-3-(4-nitrophenyl)-2-propenylidene]-4-oxo-2-thioxothiazolidin-3-yl}propanoic acid (2h) with the highest level of antimitotic activity with mean GI50/TGI values of 1.57/13.3 μM and a certain sensitivity profile against leukemia (MOLT-4, SR), colon cancer (SW-620), CNS cancer (SF-539), melanoma (SK-MEL-5), gastric cancer (AGS), human colon cancer (DLD-1), and breast cancers (MCF-7 and MDA-MB-231) cell lines. The hit compounds 2f, 2i, 2j, and 2h have been found to have low toxicity toward normal human blood lymphocytes and a fairly wide therapeutic range. The significant role of the 2-chloro-3-(4-nitrophenyl)prop-2-enylidene (Ciminalum) substituent in the 5 position and the substituent’s nature in the position 3 of core heterocycle in the anticancer cytotoxicity levels of 4-thiazolidinone derivatives have been established

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19

Gardner, Gary, James R. Sanborn, and John R. Goss. "N-Alkylaryltriazine Herbicides: A Possible Link Between Triazines and Phenylureas." Weed Science 35, no. 6 (1987): 763–69. http://dx.doi.org/10.1017/s0043174500079303.

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A comparison of the structure of the α-methylbenzyl analogue (MBAT) of atrazine with the Photosystem II herbicides atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea] suggested thatN-alkylbenzyltriazines may be a structural bridge between the triazines and the phenylureas. In the phenylureas, the addition of chlorines at the meta and/or para positions produces a marked increase in activity. Chloro-substituted derivatives of MBAT were synthesized to determine whether this structure-activity relationship also applies to the alkylaryltriazines. Addition of a chlorine to MBAT at the 4-position (CMBAT) caused a substantial increase in intrinsic activity, and a second chlorine at the 3-position (DCMBAT) caused a further increase. In direct comparisons, DCMBAT was more active in vitro than terbuthylazine [6-chloro-N-ethyl-N′-(1,1-dimethylethyl)-1,3,5-triazine-2,4-diamine], the most active chlorotriazine, and was also more active than diruon. The effects of DCMBAT were also measured on triazine-resistant pigweed (Amaranthus hybridusL. # AMACH) both in vivo and in vitro. The activity of this compound in triazine-resistant chloroplasts was intermediate between that of atrazine and diruon both in inhibition of photosynthetic electron transport and in competition for diuron binding sites, with half-maximal values falling in the micromolar range. Whole plant phytotoxicity of DCMBAT on triazine-resistant pigweed was also intermediate between that of diuron and atrazine. Since DCMBAT is a triazine with biological properties similar to that of a urea, we conclude that in a functional as well as structural sense, DCMBAT is a herbicide that is a hybrid between a triazine and a urea.

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20

Chelli, Saloua, Konstantin Troshin, Sami Lakhdar, Herbert Mayr, and Peter Mayer. "Crystal structure of 2-[chloro(4-methoxyphenyl)methyl]-2-(4-methoxyphenyl)-5,5-dimethylcyclohexane-1,3-dione." Acta Crystallographica Section E Crystallographic Communications 72, no. 3 (2016): 300–303. http://dx.doi.org/10.1107/s2056989016002085.

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In the title compound, C23H25ClO4, the cyclohexane ring adopts a chair conformation with the 4-methoxyphenyl substituent in an axial position and the chloro(4-methoxyphenyl)methyl substituent in an equatorial position. The packing features inversion dimers formed by pairs of C—H...O contacts and strands along [100] and [010] established by further C—H...O and C—H...Cl contacts, respectively.

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21

Huang, Juan-Lan, and Yun-Long Feng. "(Benzoylacetonato)chloro[3-(dimethylamino)propylamine]copper(II)." Acta Crystallographica Section E Structure Reports Online 62, no. 4 (2006): m843—m845. http://dx.doi.org/10.1107/s1600536806009949.

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In the molecular structure of the title complex, [Cu(C10H9O2)Cl(C5H14N2)], the CuII atom is in a distorted square-pyramidal geometry, coordinated by two O atoms of a benzoylacetonate ligand and two N atoms of a 3-(dimethylamino)propylamine ligand in the basal plane, while a Cl atom occupies the apical position.

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22

Reyes, Mayra, Yoanna M. álvarez, Ariadna Fuente, José A. Ruiz та Hermán Vélez-Castro. "Synthesis of 9α-chloro and Bromo-androstane Derivatives". Journal of Chemical Research 2005, № 7 (2005): 434–35. http://dx.doi.org/10.3184/030823405774309140.

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New steroids derivatives having a chlorine and a bromine atom at 9α-position were obtained from a key intermediate 5α-9(11), 16-pregnadien-3β-ol-20-one acetate. These steroids have potential anabolic/androgenic activity.

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23

Paoli-Lombardo, Romain, Nicolas Primas, Sébastien Hutter, et al. "6-Chloro-3-nitro-8-(phenylthio)-2-[(phenylthio)methyl] imidazo[1,2-a]pyridine." Molbank 2023, no. 2 (2023): M1613. http://dx.doi.org/10.3390/m1613.

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As part of our ongoing antikinetoplastid structure–activity relationship study focused on positions 2 and 8 of the 3-nitroimidazo[1,2-a]pyridine scaffold, we were able to introduce a phenylthioether moiety at both position 2 and position 8 in one step. Using a previously reported synthetic route developed in our laboratory, we obtained 6-chloro-3-nitro-8-(phenylthio)-2-[(phenylthio)methyl]imidazo[1,2-a]pyridine in 74% yield. The in vitro cell viability of this compound was assessed on the HepG2 cell line, and its in vitro activity was evaluated against the promastigote form of L. donovani, the axenic amastigote form of L. infantum and the trypomastigote blood stream form of T. b. brucei. It showed low solubility in HepG2 culture medium (CC50 > 7.8 µM), associated with weak activity against both the promastigote form of L. donovani (EC50 = 8.8 µM), the axenic amastigote form of L. infantum (EC50 = 9.7 µM) and the trypomastigote blood stream form of T. b. brucei (EC50 = 12.8 µM).

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Pająk, Małgorzata. "Microwave enhanced synthesis of halogenated derivatives of L-tyrosine labeled with deuterium in aromatic ring." Journal of Radioanalytical and Nuclear Chemistry 326, no. 1 (2020): 857–60. http://dx.doi.org/10.1007/s10967-020-07362-8.

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Abstract Three halogenated derivatives of L-tyrosine, selectively labeled with deuterium in aromatic ring, i.e., 3′-fluoro-[5′-2H]-, 3′-chloro-[5′-2H]-, and 3′-iodo-[2′,5′-2H2]-L-tyrosine, were synthesized using microwave assisted acid-catalyzed isotope exchange between 3′-fluoro-, 3′-chloro- and 3′-iodo-L-tyrosine and heavy water. The degree of deuterium incorporation was confirmed by 1H NMR spectroscopy. The spectroscopic data indicate that isotope exchange depends on the method of heating and the power of microwaves. The deuterium enrichment of 3′-fluoro-[5′-2H]- and 3′-chloro-[5′-2H]-L-tyrosine amounted to 70% and 60%, respectively, while for 3′-iodo-[2′,5′-2H2]-L-tyrosine this value was about 50% and 95% for the 2′- and 5′-position. The isotopomers were obtained in good chemical yields of 50–70%.

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25

Sabutski, Yuri E., Marina N. Semenova, Ekaterina A. Yurchenko, et al. "Synthesis and Comparative Evaluation of Polymethoxy Substituted 1,4-Naphthoquinones and their Acetyl-O-glucosides as Cytotoxic Agents." Natural Product Communications 12, no. 7 (2017): 1934578X1701200. http://dx.doi.org/10.1177/1934578x1701200721.

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Twenty five hydroxy-, chloro- and methoxy derivatives of natural and synthetic naphthazarins and their acetylated O-glycosides were synthesized. Targeted compounds were screened as cytotoxic agents on mouse Ehrlich ascites carcinoma cells using MTT test. Chloro- and methoxy-substituted naphthoquinones as well as naphthoquinone O-acetylglucosides were the most potent with IC50 in low micromolar concentration range. Glucosidation of hydroxynaphthoquinones was shown to enhance cytotoxicity, whereas methoxylation yielded both more active and less active derivatives depending on the number and position of methoxy groups. Evaluation using a phenotypic sea urchin embryo assay suggested that naphthazarins exerted their cytotoxic effects through tubulin-unrelated mechanism.

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Nauš, Petr, Martin Kuchař, and Michal Hocek. "Cytostatic and Antiviral 6-Arylpurine Ribonucleosides IX. Synthesis and Evaluation of 6-Substituted 3-Deazapurine Ribonucleosides." Collection of Czechoslovak Chemical Communications 73, no. 5 (2008): 665–78. http://dx.doi.org/10.1135/cccc20080665.

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A series of 3-deazapurine ribonucleosides 5a-5l bearing diverse C-substituents (alkyl, aryl and heteroaryl) in the position 6 were prepared by Pd-catalyzed cross-coupling reactions of either free 6-chloro-3-deazapurine ribonucleoside 4 or its acetyl protected congener 3 followed by deprotection. An improved synthesis of the starting 4-chloro-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-1H-imidazo[4,5-c]pyridine (3) was developed by the application of Vorbrüggen glycosylation of silylated nucleobase with 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose (2). None of compounds 5a-5l showed any considerable cytostatic or antiviral activity.

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27

Zeynep Ceylan and eyda Deniz Ayd n, Zeynep Ceylan and eyda Deniz Ayd n. "Investigation of the Effect of Substituent Species/Positions and Numbers on Removal of Toxicity from Chloro and Nitro Phenol Compounds with Fenton and Fenton-like Processes." Journal of the chemical society of pakistan 42, no. 5 (2020): 639. http://dx.doi.org/10.52568/000676/jcsp/42.05.2020.

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Phenol derivatives containing substutient are used intensely in industry and their presence in surface and waste water is a problem requiring urgent solution due to their tendency for bioaccumulation, cancerogenic effects, high toxicity and weak biodegradability. In this study, the degradability and toxicity of chlorinated phenols 2-CP, 2,4-DCP and 4-CP and nitrated phenols 2-NP, 2,4-DNP and 4-NP were investigated. These phenols are included on the priority toxic pollutant list within the scope of clean water regulations according to both the US EPA-2014 and the European Union (2455/2001/CE) and form serious threats to public health and aqueous ecosystems. The degradability of chloro and nitro phenols was researched by applying the Fenton/Fenton-like processes (under optimal conditions) and measuring the model pollutant concentrations, COD and TOC parameters. The effects of substituent type/position and number were determined with toxicity measurements using Vibrio fischeri bacteria (DIN/EN/ISO 11348-2). Statistical analysis was performed in detail for both Fenton/Fenton-like processes (T test) and toxicology measurement results (One-Way ANOVA) for the model pollutants (Pandlt;0.05). In the first stage of the study, model pollutant removal of 95-100%, COD removal of 64-85% / 60-77% and TOC removal efficiency of 52-65% and 40-61% were achieved respectively with Fenton and Fenton-like processes. In the second stage of the study, the results of toxicity measurements of the pollutants performed before processing found EC50(mg/L) and toxic unit values (TU) were 8.10-12.34 for 2-CP, 2.24-44.67 for 2,4-DCP, 1.20-83.33 for 4-CP, 13.43-7.44 for 2-NP, 8.92-11.21 for 2,4-DNP, and 4.77-20.9 for 4-NP, respectively. After processing, the EC50/EC20 and TU values were determined to fall to unobservable levels. According to the order obtained with toxicity measurements of 4-CP andgt; 2,4-DCP andgt; 4-NP andgt; 2-CP andgt; 2,4-DNP andgt; 2-NP, the chlor substituent had higher toxic effect compared to nitro. As the substituent numbers increase the toxicity increased; however, para position was identified to be more toxic compared to other positions. The reason for the 4 (para) position being more toxic than the 2,4 (ortho-para) position is thought to be due to the chlor or nitro linked to the 2 or ortho position binding to the OH group of phenol with a 5- and 6-member H-bridge in cis position forming a ring, which leads to inactivity.

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Bzowska, Agnieszka, Lucyna Magnowska, and Zygmunt Kazimierczuk. "Synthesis of 6-Aryloxy- and 6-Arylalkoxy-2-chloropurines and Their Interactions with Purine Nucleoside Phosphorylase from Escherichia coli." Zeitschrift für Naturforschung C 54, no. 12 (1999): 1055–67. http://dx.doi.org/10.1515/znc-1999-1210.

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The phase transfer method was applied to perform the nucleophilic substitution of 2,6- dichloropurines by modified arylalkyl alcohol or phenols. Since under these conditions only the 6-halogen is exchanged, this method gives 2-chloro-6-aryloxy- and 2-chloro-6-arylalkoxypurines. 2-Chloro-6-benzylthiopurine was synthesized by alkylation of 2-chloro-6-thiopurine with benzyl bromide. The stereoisomers of 2-chloro-6-(1-phenyl-1-ethoxy)purine were obtained from R- and S-enantiomers of sec.-phenylethylalcohol and 2,6-dichloropurine. All derivatives were tested for inhibition with purified hexameric E. coli purine nucleoside phosphorylase (PNP). For analogues showing IC50 < 10 μm, the type of inhibition and inhibition constants were determined. In all cases the experimental data were best described by the mixed-type inhibition model and the uncompetitive inhibition constant, Kiu, was found to be several-fold lower than the competitive inhibition constant, Kic. This effect seems to be due to the 6-aryloxy- or 6-arylalkoxy substituent, because a natural PNP substrate adenine, as well as 2-chloroadenine, show mixed type inhibition with almost the same inhibition constants Kiu and KiC. The most potent inhibition was observed for 6-benzylthio-2-chloro-, 6-benzyloxy-2-chloro-, 2-chloro-6-(2-phenyl-l-ethoxy), 2-chloro-6-(3-phenyl-l-propoxy)- and 2-chloro-6-ethoxypurines (Kiu = 0.4, 0.6, 1.4, 1.4 and 2.2 μm, respectively). The R-stereoisomer of 2-chloro-6-(1pheny-1-ethoxy)purine has Kiu = 2.0 μm, whereas inhibition of its S counterpart is rather weak (IC50> 12 μm). More rigid (e.g. phenoxy-), non-planar (cyclohexyloxy-), or more bulky (2,4,6-trimethylphenoxy-) substituents at position 6 of the purine base gave less potent inhibitors (IC50 = 26, 56 and >100 μm, respectively). The derivatives are selective inhibitors of hexameric “high-molecular mass” PNPs because no inhibitory activity vs. trimeric Cellulomonas sp. PNP was detected. By establishing the ligand-dependent stabilization pattern of the E. coli PNP it was shown that the new derivatives, similarly as the natural purine bases, are able to form a dead-end ternary complex with the enzyme and orthophosphate. It was also shown that the derivatives are substrates in the reverse synthetic direction catalyzed by E. coli PNP

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Barbosa, Maria Letícia de Castro, Pedro de Sena Murteira Pinheiro, Raissa Alves da Conceição, et al. "Regioselective Nucleophilic Aromatic Substitution: Theoretical and Experimental Insights into 4-Aminoquinazoline Synthesis as a Privileged Structure in Medicinal Chemistry." Molecules 29, no. 24 (2024): 6021. https://doi.org/10.3390/molecules29246021.

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The 4-aminoquinazoline scaffold is a privileged structure in medicinal chemistry. Regioselective nucleophilic aromatic substitution (SNAr) for replacing the chlorine atom at the 4-position of 2,4-dichloroquinazoline precursors is well documented in the scientific literature and has proven useful in synthesizing 2-chloro-4-aminoquinazolines and/or 2,4-diaminoquinazolines for various therapeutic applications. While numerous reports describe reaction conditions involving different nucleophiles, solvents, temperatures, and reaction times, discussions on the regioselectivity of the SNAr step remain scarce. In this study, we combined DFT calculations with 2D-NMR analysis to characterize the structure and understand the electronic factors underlying the regioselective SNAr of 2,4-dichloroquinazolines for the synthesis of bioactive 4-aminoquinazolines. DFT calculations revealed that the carbon atom at the 4-position of 2,4-dichloroquinazoline has a higher LUMO coefficient, making it more susceptible to nucleophilic attack. This observation aligns with the calculated lower activation energy for nucleophilic attack at this position, supporting the regioselectivity of the reaction. To provide guidance for the structural confirmation of 4-amino-substituted product formation when multiple regioisomers are possible, we employed 2D-NMR methods to verify the 4-position substitution pattern in synthesized bioactive 2-chloro-4-aminoquinazolines. These findings are valuable for future research, as many synthetic reports assume regioselective outcomes without sufficient experimental verification.

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30

Dhokale, Bhausaheb, Indresh Singh Yadav, Shaikh M. Mobin, and Rajneesh Misra. "Thioether linked meso functionalized BODIPY DYEmer." Journal of Porphyrins and Phthalocyanines 25, no. 05n06 (2021): 428–35. http://dx.doi.org/10.1142/s1088424621500176.

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Thioether linked meso BODIPY DYEmer 3 was synthesized by two different routes. The reaction of dipyrrothioketone 1 and 8-chloro BODIPY 2 in the presence of triethylamine followed by complexation with BF[Formula: see text] resulted in thioether linked meso functionalized BODIPY DYEmer 3. Using another route, the reaction of 8-chloro BODIPY 2 with sodium hydrosulphide (NaSH) at room temperature resulted in the thioether linked meso BODIPY DYEmer 3. The DYEmer 3 was characterized by 1H, [Formula: see text]C, [Formula: see text]B, [Formula: see text]F NMR, HRMS, and single crystal X-ray crystallography. The properties of DYEmer 3 was compared with the previously reported thioether linked [Formula: see text] and [Formula: see text] BODIPY DYEmers 4 and 5. The structural parameters indicating the intramolecular arrangements of two BODIPY units of DYEmer were compared and corelated with the observed properties. The time-dependent DFT (TD-DFT) calculations suggested that the thioether group at meso position of BODIPY 3 stabilizes the LUMO energy than 8-chloro BODIPY 2. Compared to 8-chloro BODIPY 2 the HOMO-1 of DYEmer 3 is destabilized whereas the LUMO+1 is stabilized.

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Kapadiya, Khushal M., and Ranjan C. Khunt. "Discovery of Hybrid Purine-quinoline Molecules and Their Cytotoxic Evaluation." Letters in Drug Design & Discovery 16, no. 1 (2018): 21–28. http://dx.doi.org/10.2174/1570180815666180419151742.

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Background: Apart from the “hit drugs”, there are many others being studied for their potent activity against several hostilities. To date, anticancer research has been exploited on the inherent versatility and active core skeleton of the compounds. Literature suggests that nitrogen rich molecules are most active and found in their potent cancer activity. Purine-based compounds such as olomoucine and roscovitine, which contain other heterobicyclic ring systems, are useful for the cell proliferation inhibitors in the treatment of many types of cancer. Methods: We put forward the novel purine based compounds, aryl amino-quinoline-purine by a two-step procedure. In the first step, nitrogen rich molecule was synthesized by the coupling of 2,6- dichloropurine with 3-aminoquinoline in an acidic reaction conditions at the C-6 position of purine. Aryl amines were introduced at the C-2 position by acid catalyst and using polar solvent at comparatively higher reaction conditions to furnish the desired products. Results: Stereochemical aspect was introduced for the identification of attachment of 3- aminoquinoline at the C-2/ C-6 position of purine and it was concluded by the spectral analysis (HMBC spectrum). The spectral data revealed that the first chloro-amine coupling was directed at the C-6 position rather than C-2 and the second chloro-amine coupling by various aryl amines were directed at the C-2 position. The applications of synthesized compounds were identified by their cytotoxic study against NCI-60 cell-lines. Out of nine selected molecules by NCI, 5a has shown promising response in a single dose study and GI50 value, 7.57 &#181;M indicated that it has 7.57% lethality over HOP-92 cell-line (non-small cell lung cancer panel). Conclusion: Two straightforward novelties were introduced, first stereochemical identification for chloro-amine coupling in purine either at the C-2 or C-6 position on the basis of HMBC spectrum. And a second type of uniqueness was to identify better anti-cancer agents out of synthesized scaffolds. Overall study shows that compound 5a is a novel therapeutic agent after modification for the treatment of non-small cell lung and it satisfied determined threshold growth inhibition criteria at a single dose level.

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Nikitin, Kirill V., and Nonna P. Andryukhova. "Synthesis of 5-alkyl- and 5-aryl-1,5-dihydro-2H-pyrrol-2-ones via coupling of 5-chloro-1,5-dihydro-2H-pyrrol-2-ones with organometallic compounds." Canadian Journal of Chemistry 78, no. 10 (2000): 1285–88. http://dx.doi.org/10.1139/v00-127.

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5-Chloro-1,5-dihydro-2H-pyrrol-2-ones are easily alkylated at the 5-position by organomagnesium or organozinc compounds and diethyl sodiomalonate leading to corresponding 5-alkyl-1,5-dihydro-2H-pyrrol-2-ones in high yields.Key words: organometallic compounds, alkylation, 1,5-dihydro-2H-pyrrol-2-one.

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33

Montgomery, Matthew J., Thomas J. O'Connor та Joseph M. Tanski. "Crystal structures of 4-chloropyridine-2-carbonitrile and 6-chloropyridine-2-carbonitrile exhibit different intermolecular π-stacking, C—H...Nnitrileand C—H...Npyridineinteractions". Acta Crystallographica Section E Crystallographic Communications 71, № 7 (2015): 852–56. http://dx.doi.org/10.1107/s2056989015011767.

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The two title compounds are isomers of C6H3ClN2containing a pyridine ring, a nitrile group, and a chloro substituent. The molecules of each compound pack together in the solid state with offset face-to-face π-stacking, and intermolecular C—H...Nnitrileand C—H...Npyridineinteractions. 4-Chloropyridine-2-carbonitrile, (I), exhibits pairwise centrosymmetric head-to-head C—H...Nnitrileand C—H...Npyridineinteractions, forming one-dimensional chains, which are π-stacked in an offset face-to-face fashion. The intermolecular packing of the isomeric 6-chloropyridine-2-carbonitrile, (II), which differs only in the position of the chloro substituent on the pyridine ring, exhibits head-to-tail C—H...Nnitrileand C—H...Npyridineinteractions, forming two-dimensional sheets which are π-stacked in an offset face-to-face fashion. In contrast to (I), the offset face-to-face π-stacking in (II) is formed between molecules with alternating orientations of the chloro and nitrile substituents.

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A., SYAMAL, and KUMAR D. "Bromate-Bromide Mixture as a Titrimetric Reagent for the Determination of some ortho-Hydroxyaldehydes, Acids, Hydrazides, Schiff Bases and their Metal Complexes." Journal of Indian Chemical Society Vol. 65, Feb 1988 (1988): 112–16. https://doi.org/10.5281/zenodo.6035200.

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Department of Chemistry, Regional Engineering College, Kukshetra-182 119 Department of Applied Sciences and Humanities, Kurukshetra University, Kurukshetra-192 119 Manuscript received 28 January 1982, messed 18 January 1985, accepted 11 September 1985 The quantitative determination of salicylaldehyde, 5-chloro-, 5-bromo-, 5-nitro-, 5-methoxy-, 5-hydroxy-, 4-methoxy-, 4-hydroxy-, 3-ethoxy-, 3-hydroxy and 3,5-dichloro-salicylaldehydes, and 2-hydroxy-1-naphthaldehyde, salicylic acid, 5-chloro-, 5-bromo-, 5-nitro-, 5-hydroxy-, 4-hydroxy-, 3-hydroxy-, and 3,5-dichlorosalicylic acids, Schiff bases derived from salicylaldehyde or substituted salicylaldehydes and o-aminophenol, 3-aminothiophenol, benzoylhydrazide and salicylhydrazide, and metal complexes of these Schiff bases with dioxouranium(VI) and dioxomolybdenum(VI) have been carried out by bromometric titration technique using 0.1 N KBrO2 - 0.1 N KBr solution. In general, the bromination takes place at the ortho- and para positions with respect to the OH group in the ring. if one of the positions is preoccupied by another group, bromination takes place at the other vacant position. The effects of the substituents present in the ring, temperature, time and solvent on the bromination of the compounds are discussed.

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Kayen, A. H. M., Th A. B. M. Bolsman та Th J. de Boer. "Generation of nitroxides with a chloro or nitro substituent in β-position". Recueil des Travaux Chimiques des Pays-Bas 95, № 1 (2010): 14–20. http://dx.doi.org/10.1002/recl.19760950105.

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Kranz, Olaf, and Jürgen Voss. "Electroreduction of Organic Compounds, 34 [1]. Cathodic Dehalogenation of Chloroarenes with Electron-Donating Substituents." Zeitschrift für Naturforschung B 58, no. 12 (2003): 1187–200. http://dx.doi.org/10.1515/znb-2003-1206.

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The electrochemical reduction of chlorinated arenes with electron-donating substituents, i. e. chlorotoluenes, -anisoles and -phenols, is studied. Preparative electrolyses are run in various solventsupporting electrolytes under potentiostatic and galvanostatic conditions at lead or carbon cathodes. A partial and mostly regioselective hydrodechlorination of compounds with two or more chloro substituents is possible under suitable conditions. The replacement of one single chloro substituent, in particular in a para-position, is difficult. Highly toxic and persistent oligochloro derivatives are thus transformed into less problematic compounds with a low degree of chlorination. The chlorine content of real-life materials such as extracts of soil contaminated with chlorinated phenols and Nitrofen® can also be significantly decreased by electroreduction.

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Čapek, Petr, Miroslav Otmar, Milena Masojídková, Ivan Votruba, and Antonín Holý. "A Facile Synthesis of 9-Deaza Analogue of Olomoucine." Collection of Czechoslovak Chemical Communications 68, no. 4 (2003): 779–91. http://dx.doi.org/10.1135/cccc20030779.

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Heating of 6-(benzylamino)-2-chloro-9-deazapurine (3) with ethanolamine afforded 6-(benzylamino)-2-[(2-hydroxyethyl)amino]-9-deazapurine (8). Its treatment with formaldehyde in alkaline solution, after protection of the OH group with DMTr, led to hydroxymethylation at position 9. Conversion of the hydroxymethyl group to methyl was performed by catalytic hydrogenation under simultaneous deprotection, which resulted in the formation of the 9-deaza analogue 1 of olomoucine. Compound 1 does not exhibit any significant in vitro cell growth inhibition of CCRF-CEM, HeLa and L-1210 cell lines. Cytostatic activity was found in 6-(benzylamino)-9-deazapurine (2) and its 2-chloro derivative 3 in CCRF-CEM cells with IC50 13.3 and 15.8 μM, respectively.

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K¨ohler, Thomas, Hans Pritzkow, and Walter Siebert. "[3+1]-Cyclisierungen zu Tetraboraporphyrinogenen / [3+1]-Cycloadditions with Formation of Tetraboraporphyrinogenes." Zeitschrift für Naturforschung B 57, no. 10 (2002): 1101–7. http://dx.doi.org/10.1515/znb-2002-1004.

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Abstract2,5-Bis(chloro-2,2,6,6-tetramethylpiperidinoboryl)thiophene (1) and 2,5-bis(chloro-diisopropylaminoboryl) pyrrol (4) react with two equivalents of 2-lithiothiophenide to yield the corresponding 2,5-diborylheteroarenes (2,5) in which two boryl groups connect three heteroarenes. After lithiation of the terminal thiophenes of both compounds in 5,5'-position their reactions with the diborylthiophene 1 as well as with diborylpyrrol 4, lead to tetraboraporphyrinogenes (3, 6), the latter being the first tetraboratetraazaporphyrinogene. By silicon / boron exchange of 1-trimethylsilylimidazol with the 2,5-diborylpyrrol 4 the 2,5-bis(imidazolyldiisopropylamino- boryl)pyrrol 7 is formed, which reacts with BH3 and BEt3 to give the N-borane adducts of 7. The spectroscopic data and four X-ray structure analyses are reported.

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Okamoto, Yoshinori, Hideto Jinno, Shinji Itoh, and Shinya Shibutani. "Less Carcinogenic Chlorinated Estrogens Applicable to Hormone Replacement Therapy." International Journal of Molecular Sciences 22, no. 13 (2021): 7222. http://dx.doi.org/10.3390/ijms22137222.

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Human estrogens prescribed for hormone replacement therapy (HRT) are known to be potent carcinogens. To find safer estrogens, several chlorinated estrogens were synthesized and their carcinogenic potential were determined. A pellet containing either 2-chloro-17β-estradiol (2-ClE2) or 4-chloro-17β-estradiol (4-ClE2) was implanted subcutaneously for 52 weeks into August Copenhagen Irish (ACI) rats, a preferred animal model for human breast cancer. 17β-Estradiol (E2) frequently induced mammary tumors while both 2-ClE2 and 4-ClE2 did not. Their 17α-ethinyl forms, thought to be orally active estrogens, were also synthesized. Neither 2-chloro-17α-ethinylestradiol (2-ClEE2) nor 4-chloro-17α-ethinylestradiol (4-ClEE2) induced tumors. The less carcinogenic effects were supported by histological examination of mammary glands of ACI rats treated with the chlorinated estrogens. A chlorine atom positioned at the 2- or 4-position of E2 may prevent the metabolic activation, resulting in reducing the carcinogenicity. 2-ClE2 and 4-ClE2 administered subcutaneously and 2-ClEE2 and 4-ClEE2 given orally to ovariectomized rats all showed uterotrophic potency, albeit slightly weaker than that of E2. Our results indicate that less carcinogenic chlorinated estrogens retaining estrogenic potential could be safer alternatives to the carcinogenic estrogens now in use for HRT.

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Ouyang, Xi-Lin, Miao Ouyang, and Shi-Wen Huang. "6-Chloro-2-phenyl-3-(2-phenylethynyl)quinoxaline." Acta Crystallographica Section E Structure Reports Online 68, no. 6 (2012): o1741. http://dx.doi.org/10.1107/s1600536812020776.

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In the title compound, C22H13ClN2, the quinoxaline ring system is close to planar [maximum deviation = 0.061 (2) Å]. The phenyl ring at the 2-position and the phenyl ring of the phenylethynyl substituent make dihedral angles of 49.32 (7) and 11.99 (7) °, respectively, with the quinoxaline mean plane. The two phenyl rings are inclined to one another by 61.27 (9)°. In the crystal, molecules are linked by C—H...π and π–π interactions [centroid–centroid distances = 3.6210 (12) and 3.8091 (12) Å].

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Bolibrukh, L. D., I. I. Hubytska, A. I. Karkhut, R. T. Konechna, S. V. Polovkovych, and V. P. Novikov. "The study of the interaction of 2-chloro- and 2,3-dichloro-5(8)-RO-1,4-naphtoquinones with CH-acids." Voprosy Khimii i Khimicheskoi Tekhnologii, no. 6 (December 2022): 12–18. http://dx.doi.org/10.32434/0321-4095-2022-145-6-12-18.

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The regioselectivity of the reaction of 2-chloro- and 2,3-dichloro-5-substituted naphthoquinones with CH-acids is studied. It is shown that the nature of the substituent in 5-RO-1,4-naphthoquinones plays the main role in the predominant formation of one of the possible regioisomers in the reactions of nucleophilic substitution. It is substantiated that the orientation of the nucleophilic attack by CH-acid on the C3 atom of 5-RO-1,4-naphthoquinones is due to the fact that the 5-methoxy and 5-acetoxy groups have a passivating effect on the electron-accepting properties of the C4=O group due to the positive conjugation effect. As a result, the electrophilic center appears in position 3. It is established that the interaction of 2- or 3-chloro-substituted 5-RO-1,4-naphthoquinones with CH-acids proceeds with the formation of 2- and 3-addition products with a preference for products of substitution of the chlorine atom in 3rd position. The structure of the regioisomers is confirmed by spectral data and by countersynthesis.

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Ciarka, Kamil, Radoslaw Olszewski, Tadeusz Praczyk, and Juliusz Pernak. "Synthesis and characterization of herbicidal ionic liquids based on (4-chloro-2-methylphenoxy)acetate and phenoxyethylammonium." Chemical Papers 75, no. 7 (2021): 3607–15. http://dx.doi.org/10.1007/s11696-021-01610-1.

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AbstractTen ionic liquids containing the (4-chloro-2-methylphenoxy)acetate (MCPA) anion and domiphen derived phenoxyethylammonium cation were synthesized. The obtained compounds differed in terms of the substitution of the phenoxyethylammonium group in the ring (the presence of a methyl group in the meta or para positions and the presence of chlorine in the para position) as well as the length of the alkyl chain (from hexyl to tetradecyl). The basic physicochemical properties of the obtained ionic liquids (solubility and thermal stability) were characterized and their structures were confirmed. The herbicidal activity of the compounds was tested under greenhouse conditions using cornflower (Centaurea cyanus L.) as the test plant.

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43

Akkurt, Mehmet, Shaaban K. Mohamed, Antar A. Abdelhamid, Abdel-Aal M. Gaber, and Mustafa R. Albayati. "9-(3-Bromo-5-chloro-2-hydroxyphenyl)-10-(2-hydroxyethyl)-3,6-diphenyl-3,4,9,10-tetrahydroacridine-1,8(2H,5H)-dione." Acta Crystallographica Section E Structure Reports Online 70, no. 6 (2014): o663—o664. http://dx.doi.org/10.1107/s1600536814010460.

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In the title compound, C33H27BrClNO4, the dihydropyridine ring adopts a flattened boat conformation. The molecular conformation is stabilized by an intramolecular O—H...O hydrogen bond, with anS(8) ring motif. In the crystal, O—H...O, C—H...O and C—H...Cl hydrogen bonds, and C—H...π interactions link the molecules, forming a three-dimensional network. In the acridinedione ring system, the two ring C atoms at the 2- and 3-positions, and the C atom at the 6-position and the atoms of the phenyl ring attached to the C atom at the 6-position are disordered over two sets of sites with occupancy ratios of 0.783 (5):0.217 (5) and 0.526 (18):0.474 (18), respectively.

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44

Koutek, Bohumír, Lubomír Musil, Jiří Velek, and Milan Souček. "Fluorescence behaviour of some 4-substituted halobenzenes." Collection of Czechoslovak Chemical Communications 50, no. 8 (1985): 1753–63. http://dx.doi.org/10.1135/cccc19851753.

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The fluorescence characteristics of 4-substituted chloro and fluorobenzenes I and II were studied in isooctane and acetonitrile solutions. It was found that all compounds exhibit a weak (substituent and solvent dependent) fluorescence in the range 305-370 nm with quantum yields 1.2 . 10-2-2.3 . 10-1. The relation between the substituent nature and fluorescence band position may be quantified by log νf~ = ρσp + log νf~0, the magnitude of the shift paralleling the donor strength of the substituent. Fluorescence quantum yields are increased approximately by a factor 2 on going from isooctane to acetonitrile and solvent-induced shifts are proportional to the static dipole moment change Δμ which occurs upon excitation. Radiative decay rate varies only slightly around a mean value of 5 . 107 s-1 and shows no substantial difference between chloro (I) and fluoro (II) derivatives. The non-radiative decay rate (of the order ~ 109 s-1) was found to be about 5 times higher in the case of chloro compounds due to the more efficient S1 - Tn intersystem crossing.

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45

Clewley, Robin G., Alfred Fischer, and George N. Henderson. "ipso Nitration in p-halophenyl ethers." Canadian Journal of Chemistry 67, no. 9 (1989): 1472–79. http://dx.doi.org/10.1139/v89-224.

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Addition of nitronium ion ipso to halogen occurs on nitration of the p-haloanisoles in acetic anhydride at −60 °C. In the cases of p-fluoro- and p-chloro-anisole, addition of the nitronium ion is reversible and only small amounts of ipso products are obtained. With p-bromoanisole nitrodebromination occurs. When p-halophenyl ethers containing a trapping substituent, e.g., 2-(4-chlorophenoxy)-2-methylpropanoic acid, are used as substrates, substantial amounts of the spiro diene with nitro ipso to halogen, e.g., 3,3-dimethyl-8-chloro-8-nitro-1,4-dioxaspiro[4.5]deca-6,9-dien-2-one, can be isolated. The results demonstrate that extensive ipso attack at the halogen-substituted position is general in the nitration of p-halophenyl ethers. Keywords: ipso nitration, ether, diene, p-haloanisole.

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46

Saalfrank, Rolf W., Jochen Nachtrab, and Stephan Reck. "Synthese und Aggregatbildung eines 5-Hydroxy-2,5-dihydropyrrols. Enantiomerenreine, eindimensionale Stränge durch Wasserstoffbrückenbindungen und chiroselektive Selbstorganisation/Synthesis and Aggregation of a 5-H ydroxy-2,5-dihydropyrrole. Enantiomerically Pure, One-dimensional Strands via Hydrogen Bonds and Chiroselective Self Organization." Zeitschrift für Naturforschung B 54, no. 2 (1999): 179–86. http://dx.doi.org/10.1515/znb-1999-0205.

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Reaction of dimethyl 1,3-acetonedicarboxylate 8 with oxalylchloride 2 and magnesium chloride as catalyst yielded 2,3-dioxo-2,3-dihydrofuran 9, which is in equilibrium with tautomer 10 (9:10 = 1:2). Addition of thionyl chloride to a mixture of 9/10 afforded 3-chloro-2(5H)-furanone 11. The structure of 11 was unequivocally established by X-ray diffraction, which indirectly proved the structure of 10 as well. Ring opening of 11 by nucleophilic attack with benzylamine 14 in C2-position and subsequent recyclization led to racemic 3-chloro-5-hydroxy-2-oxo-2,5-dihydropyrrole 15. According to a single crystal X-ray analysis, 15 aggregates via stereospecific self selection through hydrogen bonds to give chiroselectively the one-dimensional strands ∞1[(S)-15] and ∞1[( R)-15]

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47

Mustafin, Akhat G., Yury S. Zimin, Ildus B. Abdrakhmanov, and Vakil M. Sharafutdinov. "The interaction of piperylene and its chlorine derivatives with aromatic amines." Butlerov Communications 58, no. 4 (2019): 22–33. http://dx.doi.org/10.37952/roi-jbc-01/19-58-4-22.

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The article considers the possibility of introducing a pentenyl radical into the structure of aromatic amines by the interaction of the latter with piperylene and its chlorine derivatives, 4-chloro-2-pentene and 3,4-dichloro-2-pentene. Direct alkenylation of aniline with piperylene in the presence of Lewis acids leads to C-alkenyl arylamines. The most effective catalyst is AlCl3. Along with the expected 2- and 4-(1-methyl-2-butenyl) anilines, the formation of 2,4-di- and 2,4,6-tri-(1-methyl-2-butenyl) anilines is observed, the latter being virtiually the only product in the reaction with a 5-fold excess of piperylene. In addition to Lewis acids, H3PO4 deposited on kieselguhr or silica gel, as well as polyphosphoric acid, were used to catalyze this reaction. Under the action of these catalysts, ortho- and para-alkenylated anilines are mainly formed, and the yield of the ortho-isomer, reaching 34%, always exceeds the yield of the para-product. It is possible that, under these conditions, N-alkenylation occurs simultaneously with direct C-alkenylation followed by an amino rearrangement. The yield of the 2,4-dialkenyl product does not exceed 8%, and trialkenylated aniline is completely absent. The optimal reaction temperature is in the range of 180-200 °C, at higher temperatures the yield of the target products decreases due to the polymerization of piperylene. Various aniline derivatives are also involved in the reaction with piperylene. When one of the ortho positions in the arylamine molecule is occupied, as in ortho-toluidine or in 2-chloroaniline, a mixture of the three products is formed in comparable amounts. The reaction of meta-toluidine with piperylene also leads to the mixture of three products, and the substitution does not affect the 2-position between the amino and methyl groups. If both ortho-positions are occupied, as in 2-methyl-6-ethylaniline, the reaction is quite successfully under way in the para-position (yield is 61%). To increase the selectivity of the process, the alkylation of aromatic amines is best carried out not by piperylene, but by its chlorine derivatives. The reaction of aniline with 4-chloro-2-pentene takes place in the environment of triethylamine and leads to N-(1-methyl-2-butenyl) aniline with a yield of 80%. Other primary and secondary arylamines react in the same way. The reaction with 3,4-dichloro-2-pentene proceeds under more severe conditions. If the reaction of aromatic amines with 4-chloro-2-pentene is carried out not in triethylamine medium, but in an excess of arylamine itself as a solvent, then not N- but C-substituted products are formed. The reaction proceeds as a consequitive-simultameous process. In the first stage, N-alkenylation occurs with the formation of N-(1-methyl-2-butenyl) arylamine followed by an amino rearrangement of Claisen under the catalytic action of evolved HCl. Alongside with the obvious predominance of ortho-substituted arylamine (64-82%), para-isomers and, in some cases 5-12% of 2,4- or 2,6-disubstituted compounds were found in the reaction products. The amino rearrangement in the interaction of arylamines with 3,4-dichloro-2-pentene proceeds with exceptional ortho-selectivity. Alkyl groups at nitrogen and ortho positions accelerate, and ortho-chloro, para-methyl, 2,4-dimethyl substituents slow down the process, while the meta-methyl group has no significant effect. The same dependence was observed in the case of 4-chloro-2-pentene. Thus, pentenyl fragment can be introduced in various ways into the structure of aromatic amines: by direct interaction with piperylene in the presence of catalysts, N-alkenylation of 4-chloro-2-pentene and 3,4-dichloro-2-pentene in triethylamine medium and reaction of arylamines with chlorine derivatives of piperylene, accompanied by an amino rearrangement of Claisen.

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48

Su, Bi-Yun, Jia-Xiang Wang, Xiang Liu, and Qian-Ding Li. "Isomeric 3- and 4-chloro-N-[1-(1H-pyrrol-2-yl)ethylidene]aniline." Acta Crystallographica Section C Crystal Structure Communications 69, no. 5 (2013): 522–25. http://dx.doi.org/10.1107/s0108270113007889.

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The title isomers, namely 3-chloro-N-[1-(1H-pyrrol-2-yl)ethylidene]aniline, (I), and 4-chloro-N-[1-(1H-pyrrol-2-yl)ethylidene]aniline, (II), both C12H11ClN2, differ in the position of the chlorine substitution. Both compounds have the basic iminopyrrole structure, which shows a planar backbone with similar features. The dihedral angle formed by the planes of the pyrrole and benzene rings is 75.65 (7)° for (I) and 86.56 (8)° for (II). The H atom bound to the pyrrole N atom is positionally disordered and partial protonation occurs at the imino N atom in (I), while this phenomenon is absent from the structure of (II). Packing interactions for both compounds include intermolecular N—H...N hydrogen bonds and C—H...π interactions, forming centrosymmetric dimers for both (I) and (II).

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49

Franchetti, P., L. Messini, L. Cappellacci, et al. "8-Aza Derivatives of 3-Deazapurine Nucleosides. Synthesis and in vitro Evaluation of Antiviral and Antitumor Activity." Antiviral Chemistry and Chemotherapy 4, no. 6 (1993): 341–52. http://dx.doi.org/10.1177/095632029300400606.

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The syntheses of 4-amino-1-(β-D-ribofuranosyl)-1 H-1,2,3-triazolo[4,5-c]pyridine (8-aza-3-deazaadenosine, 1), 4-amino-1-(2-deoxy-β-D- erythro-pentofuranosyl)-1 H-1,2,3-triazolo[4,5-c]pyridine (2′-deoxy-8-aza-3-deazaadenosine, 2), and their N8 and N7 glycosylated analogues (12,13, 21,22) and 4-amino-1-(2,3-dideoxy-β-D- erythro-pentof uranosyl)-1 H-1,2,3-triazolo [4,5-c]pyridine (2′,3′-dideoxy-8-aza-3-deazaadenosine, 3) were carried out by glycosylation of the 4-chloro-3 H-1,2,3-triazolo[4,5-c]pyridine anion. The anomeric configuration as well as the position of glycosylation were determined by 1H-, 13C-NMR, UV and N.O.E. difference spectroscopy. Nucleoside (2) and its parent compound 2′-deoxy-3-deazaadenosine were found active against ASFV and VSV. The 4-chloro-2-(β-D-ribofuranosyl)-2 H-1,2,3-triazolo[4,5-c] pyridine (9) was active against Coxsackie B1, whereas none of the 8-aza-3-deaza purine nucleosides, compound (3) included, was active against HIV-1. The 6-chloro derivatives of 8-aza-3-deazapurine ribo- and 2′-deoxyribonucleosides (11) and (20) showed some activity against LoVo human colon adenocarcinoma.

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50

Derikov, Yaroslav I., Daniil R. Belousov, Alexander V. Finko, et al. "Novel Mesogenic Vinyl Ketone Monomers and Their Based Polymers." Polymers 15, no. 1 (2022): 5. http://dx.doi.org/10.3390/polym15010005.

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In the present research, we have synthesized new vinyl ketone monomers with mesogenic substituents, namely, 8-(3′-chloro-4′-pentyl-[1,1′-biphenyl-4-oxy)oct-1-en-3-one (BVK) and 8-[2′-chloro-4‴-octyl-[1,1′:4′,1″:4″,1‴-quaterphenyl-4-oxy]oct-1-en-3-one (QVK). The comparison of BVK, QVK, and previously synthesized 8-((4″-((1R,4S)-4-butylcyclohexyl)-2′-chloro-[1,1′,4′,1″-terphenyl]-4-yl)oxy)oct-1-en-3-one (TVK) has revealed that all of them are able to form crystals, while their ability to exhibit liquid crystalline behavior depends on the number of phenyl substituents attached to the para-position of the phenoxy group and is observed for TVK and QVK only. All of the monomers are able to achieve self-polymerization upon heating and free radical polymerization in bulk or in solution under the action of the common radical initiator AIBN. We have also succeeded in the RAFT polymerization of the synthesized vinyl ketones BVK and TVK using asymmetrical trithiocarbonates. The synthesized poly(vinyl ketones) exhibit LC behavior and are able to undergo photodegradation upon UV irradiation.

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Journal articles on the topic 'Chloro Position'

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