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Journal articles on the topic 'Crystallography. Carbon compounds. Stereochemistry'

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Published: 4 June 2021

Last updated: 9 February 2022

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1

Coll, JC, BW Skelton, AH White, and AD Wright. "Tropical Marine Algae. II. The Structure Determination of New Halogenated Monoterpenes From Plocamium hamatum (Rhodophyta, Gigartinales, Plocamiaceae)." Australian Journal of Chemistry 41, no. 11 (1988): 1743. http://dx.doi.org/10.1071/ch9881743.

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The structure determinations of new halogenated monoterpenes, isolated from collections of Plocamium hamatum J. Agardh , are reported. One collection of P. hamatum afforded (1R*,2R*,4S*,5R*,1′E)-1,2,4- trichloro-5-(2′-chloroethenyl)-1,5-dimethylcyclohexane (1) whose relative stereochemistry was determined by X-ray crystallography. Extensive use of two-dimensional carbon-hydrogen correlation experiments enabled unambiguous assignments of proton and carbon resonances to be made for this new compound. Complete carbon assignments for the related metabolite mertensene (2) are reported. A second col

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2

Sugita, Kazuyuki, Motoi Kuwabara, Ami Matsuo, Shogo Kamo, and Akinobu Matsuzawa. "Stereoselective Convergent Synthesis of Carbon Skeleton of Cotylenin A Aglycone." Synthesis 53, no. 12 (2021): 2092–102. http://dx.doi.org/10.1055/s-0040-1706684.

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AbstractIn this paper, the synthesis of the carbon skeleton of cotylenin A aglycone is described. The key reactions, including an intramolecular aldol reaction, an aldol coupling reaction, and a ring-closing metathesis, allow for the effective and stereoselective access to the carbon skeleton of cotylenin A aglycone. The stereochemistry was confirmed by single-crystal X-ray crystallographic analyses of related compounds.

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3

Bernhardt, Paul V., Raymond M. Carman, and Tri T. Le. "The Stereo Structures of Some Mycophenolic Acid Derivatives." Australian Journal of Chemistry 60, no. 5 (2007): 354. http://dx.doi.org/10.1071/ch06481.

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4

Bowden, BF, JC Coll, LM Engelhardt, et al. "Studies of Australian Soft Corals .XXXVII. The Structure Determination of 2 Cembranolide Diterpenes From Soft Corals of the Genus Efflatounaria (Coelenterata, Octocorallia, Alcyonacea)." Australian Journal of Chemistry 39, no. 1 (1986): 123. http://dx.doi.org/10.1071/ch9860123.

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Two isomeric 7,8-epoxycembra-3,11,15-trien-16,2-olides have been isolated from different species of the soft coral genus Efflatounaria. The structure of each was deduced spectroscopically , and the relative stereochemistry of one was determined by X-ray crystallography. The absolute stereochemistry of each cembranolide was obtained by chemical correlation with known compounds.

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5

Cambie, RC, HM Craw, CEF Rickard, et al. "An Oxidative Decarboxylation of 7-Oxopodocarpic Acid Derivatives." Australian Journal of Chemistry 43, no. 5 (1990): 883. http://dx.doi.org/10.1071/ch9900883.

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Treatment of the 7-oxopodocarpic acid derivatives (1) and (3) with 2,3-dichloro-5,6-dicyanobenzoquinone affords the conjugated dienones (5) and (6) directly. The latter compounds have potential as optically active relays for the synthesis of 3-oxygenated diterpenoids . The stereochemistry of an epoxide (7) formed from the dienone (5) has been confirmed by X-ray crystallography.

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6

Kasai, Masaji, Herman Ziffer, and J. V. Silverton. "Enantioselective ester hydrolyses using Rhizopusnigricans: stereoselective synthesis and absolute stereochemistry of (−)-cis- and (−)-trans-1-hydroxy-4-methyl-1,2,3,4-tetrahydronaphthalene." Canadian Journal of Chemistry 63, no. 6 (1985): 1287–91. http://dx.doi.org/10.1139/v85-219.

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Enantioselective hydrolysis of racemic acetates of cis- and trans-1-hydroxy-4-methyl-1,2,3,4-tetrahydronaphthalene using Rhizopusnigricans yields chiral alcohols. The absolutestereochemistry of these compounds, and that of a key intermediate in their stereoselective synthesis, r-1-hydroxy-2,t-bromo-4,c-methyl-1,2,3,4-tetrahydronaphthalene, were determined by chemical transformations to 1-oxo-4-methyl-1,2,3,4-tetrahydronaphthalene of known absolute stereochemistry. The relativestereochemistry of the acetate of the key intermediate was established by X-ray crystallography.

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7

Kalabin, G. A., L. B. Krivdin, V. V. Shcherbakov, and B. A. Trofimov. "Carbon-to-carbon coupling constants - a new guide in the stereochemistry of heteroatomic compounds." Journal of Molecular Structure 143 (March 1986): 569–72. http://dx.doi.org/10.1016/0022-2860(86)85327-3.

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8

Tiecco, Marcello, and Marco Tingoli. "Regiochemistry and stereochemistry of nickel-promoted, carbon-carbon bond-forming reactions of cyclic sulfur compounds." Journal of Organic Chemistry 50, no. 20 (1985): 3828–31. http://dx.doi.org/10.1021/jo00220a029.

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9

Rowe, JE, and DA Papanelopoulos. "Mechanisms of Nucleophilic Attack at Carbon-Nitrogen Double Bonds. The Reaction of Benzohydrazonoyl Compounds With Methoxide Ion." Australian Journal of Chemistry 48, no. 12 (1995): 2041. http://dx.doi.org/10.1071/ch9952041.

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Rate data for the reaction of a number of benzohydrazonoyl compounds with methoxide ion are reported. The stereochemistry of the products was determined by h.p.l.c. The mechanism of the reactions and the stereochemistry of the products resulting from an addition-elimination mechanism are discussed.

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10

Anwar, E. M. Noreljaleel. "Long-range proton–carbon coupling constants for the determination of the stereochemical structure of organic compounds." Journal of The Faculty of Science and Technology, no. 7 (August 17, 2021): 125–31. http://dx.doi.org/10.52981/jfst.vi7.965.

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A new methods for elucidating stereochemistry of organic compounds was developed on the basis of long-range proton–carbon coupling constants (2,3JC,H) and interpreting spin-coupling constants (3JH,H). Reaction of compound containing pyrin ring with nucleophile reagent was done to open the ring. HSQC-TOCSY experiments one of the new NMR spectroscopy method used to measure this values of spin-coupling constants and elucidating the stereochemistry of the product.

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11

Jackson, WR, ID Rae, and MG Wong. "The Stereochemistry of Organometallic Compounds .XXVII. Nucleophilic and Electrophilic Substitution-Reactions of Conformationally Restricted Arenechromium Compounds." Australian Journal of Chemistry 39, no. 2 (1986): 303. http://dx.doi.org/10.1071/ch9860303.

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The regioselectivity of reaction of tricarbonyl (1,1- dimethylindane )chromium with selected electrophiles and nucleophiles has been shown to be influenced by the preferred conformation of the tricarbonylchromium group. Nucleophiles preferentially react at carbon atoms eclipsed by a chromium-carbonyl bond and electrophiles at carbon atoms in staggered positions. When similar reactions were attempted with some chelated arenechromium dicarbonyl phosphorus compounds only low yields of substitution products were obtained.

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12

Döpp, Dietrich, Sabine Jüschke, and Gerald Henkel. "Dicyanomethylene Compounds as Cyanation Reagents." Zeitschrift für Naturforschung B 57, no. 4 (2002): 460–70. http://dx.doi.org/10.1515/znb-2002-0412.

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Ethenetetracarbonitrile (2, in benzene solution) and 1,3-dioxoindan-2-ylidene propanedinitrile (4, in ethanol or acetonitrile solution) act on N-aryl-2,3-dihydro-1H-benz[d,e]isoquinolines 6a-d and N-aryl-6,7-dihydro-5H-dibenz[c,e]azepines 11a-d via hydride abstraction followed by addition of cyanide to the iminium carbon atom forming the corresponding 1- and 5-carbonitriles 9a-d and 13a-d, respectively, in moderate to medium yields.Additionally , the known 1,3-dihydroxy-2H-inden-2-ylidenepropanedinitrile 15 and a novel dispirocyclopropane (17) are formed from 4 in the reaction with 6 in aceton

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13

Jabeen, Bushra, and Naheed Riaz. "Isolation and Characterization of Limonoids from Kigelia africana." Zeitschrift für Naturforschung B 68, no. 9 (2013): 1041–48. http://dx.doi.org/10.5560/znb.2013-3096.

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Two new limonoids, 1-O-deacetyl-2a-methoxykhayanolide (1) and kigelianolide (2), together with deacetylkhayanolide E (3), 1-O-deacetyl-2α-hydroxykhayanolide E (4) and khayanolide B (5) were isolated from the ethyl acetate-soluble fraction of the methanolic extract of Kigelia africana. The structures of these limonoids (1-5) were elucidated by the combination of 1D (1H and 13C NMR) and 2D (HMQC, HMBC and COSY) NMR spectroscopy and mass spectrometry (EIMS, HREIMS), and in comparison with literature data of related compounds. The structure of compound 1 was further confirmed by X-ray crystallogra

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14

Clarke, Jeffery D., Keith Vaughan, and Valerio Bertolasi. "1,4,8,11-Tetra[2-aryl-1-diazenyl]-1,4,8,11-tetraazacyclotetradecanes — Synthesis, characterization, and X-ray crystallography of the first tetrakistriazenes to be reported." Canadian Journal of Chemistry 84, no. 10 (2006): 1280–89. http://dx.doi.org/10.1139/v06-090.

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The reactions of a series of arene diazonium salts with 1,4,8,11-tetraazacyclotetradecane (cyclam) afford the novel compounds, the 1,4,8,11-tetra[2-aryl-1-diazenyl]-1,4,8,11-tetraazacyclotetradecanes (1a–1f), which are the first examples of tetrakistriazenes to be reported. The tetrakistriazenes were characterized by IR spectroscopy, proton and carbon NMR, elemental analysis, high resolution electrospray mass spectrometry, and X-ray crystallography. The analogous reaction of a diazonium salt with 1,4,7-triazacyclononane or 1,5,9-triazacyclododecane yields the tristriazenes 2, 3a, and 3b. The s

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15

Mojtahedi, Mohammad M., Kiana Darvishi, M. Saeed Abaee, and Mohammad R. Halvagar. "Synthesis and fluorescence studies of novel bisarylmethylidene derivatives of 2-methoxy-2-methyl-1,3-dioxan-5-one." Canadian Journal of Chemistry 95, no. 7 (2017): 785–91. http://dx.doi.org/10.1139/cjc-2017-0099.

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The first general procedure is described for the synthesis of novel bisarylmethylidenes of 2-methoxy-2-methyl-1,3-dioxan-5-one 1. Thus, several derivatives of 3 are obtained rapidly in high yields by reacting 1 with different aldehydes in the presence of catalytic quantities of pyrrolidine in EtOH at room temperature. Upon completion of the reactions, products are obtained directly by spontaneous precipitation avoiding time consuming and expensive chromatographic separations. All products were characterized by proton and carbon NMR spectroscopy methods, and in one case, the proposed structure

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16

David, Michèle, Jean Sauleau та Armelle Sauleau. "Époxydes α-éthyléniques et phénate de sodium: accès à des éthers phénoliques et phénols ortho-allyliques". Canadian Journal of Chemistry 63, № 9 (1985): 2449–54. http://dx.doi.org/10.1139/v85-405.

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The ring cleavage reactions of α-ethylenic epoxides by sodium phenoxide afforded a mixture of products. Problems of competitive attack by this nucleophile, at the less substituted carbon (compounds A) or at the β-ethylenic carbon atom (compounds B and C), were encountered and could be resolved by judicious choice of reaction conditions (solvents, stereochemistry of the oxiranes). The regioselectivity of the attack was dependent on the transition states, implying weak steric hindrance and a conjugation oxirane – double bond.

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17

Anastasiou, D., EM Campi, H. Chaouk, et al. "The Stereochemistry of Organometallic Compounds. LX. Rhodium-Catalyzed Reactions of Hydrogen and Carbon Monoxide With Alkenylanilines." Australian Journal of Chemistry 47, no. 6 (1994): 1043. http://dx.doi.org/10.1071/ch9941043.

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Rhodium- catalysed reactions of o- or p- cyano-N-allylanilines with H2/CO give N- arylpyrrolidine aldehydes resulting from a double hydroformylation sequence. In contrast reactions of o- or p-methyl-N-allylanilines or N- allylaniline itself with H2/CO give ' dimeric ' compounds resulting from self-condensation reactions of an initially formed hydroformylation product together with varying amounts of the double hydroformylation product. Similar reactions of o-cyano-N-but-3-enylanilines give low yields of double hydroformylation products and major products arising from hydrogenation or cross cou

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18

Ohshita, Joji, Hiroyuki Niwa, and Mitsuo Ishikawa. "Silicon−Carbon Unsaturated Compounds. 59. Stereochemistry in Addition of Carbonyl Compounds to Silenes Generated Photochemically frommeso- andrac-1,2-Diethyl-1,2-dimethyldiphenyldisilane." Organometallics 15, no. 21 (1996): 4632–38. http://dx.doi.org/10.1021/om960259j.

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19

Paterson, Danielle L., and David Barker. "Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B." Beilstein Journal of Organic Chemistry 11 (February 17, 2015): 265–70. http://dx.doi.org/10.3762/bjoc.11.29.

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The synthesis of the unique furo[2,3-b]chromene ring system found in hyperaspidinols A and B, acylphloroglucinols from Hypericum chinense has been achieved in twelve steps. By comparison of the NMR spectra of the synthesized compounds with those of the natural products, a relative stereochemistry is suggested, especially that of the ketal carbon.

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20

Ji, Yeong Kwang, Seon Min Lee, Na-Hyun Kim, et al. "Stereochemical Determination of Fistularins Isolated from the Marine Sponge Ecionemia acervus and Their Regulatory Effect on Intestinal Inflammation." Marine Drugs 19, no. 3 (2021): 170. http://dx.doi.org/10.3390/md19030170.

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By activity-guided fractionation based on inhibition of nitric oxide (NO) and prostaglandin E2 (PGE2), six fistularin compounds (1–6) were isolated from the marine sponge Ecionemia acervus (order Astrophorida). Based on stereochemical structure determination using Mosher’s method, fistularin-3 was assigned as a new stereoisomer. On the basis of the stereochemistry of fistularin-3, the stereochemical homogeneity of all six compounds was established by comparing carbon and proton chemical shifts. For fistularin-1 (1) and -2 (2), quantum calculations were performed to confirm their stereochemistr

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21

Wahba, Haytham, Ahmed Mansour, Julien Vanasse, et al. "The organomercurial lyase Merb possesses unique metal-binding properties." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C1680. http://dx.doi.org/10.1107/s2053273314083193.

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Select bacterial strains survive in mercury-contaminated environments due to acquisition of a transferable genetic element known as the mer operon. The mer operon typically encodes for a series of proteins that includes two enzymes, MerA and MerB. The organomercurial lyase (MerB) cleaves carbon-mercury bonds of organomercurial compounds yielding ionic mercury Hg (II) and a reduced-carbon compound. The Hg (II) ion product remains bounds until it is shuttled directly to the mercuric ion reductase (MerA) to be reduced. Based on NMR spectroscopy and X-ray crystallography studies1, we have determin

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22

Chin, Anna Fu Oi, Lyall R. Hanton, and Rex T. Weavers. "The Chemistry of Lauren-1-ene. XVII Preparation of Unsaturated Oxa and Aza Tetracycles." Australian Journal of Chemistry 50, no. 4 (1997): 279. http://dx.doi.org/10.1071/c96104.

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Several lauren-1-ene-derived compounds containing an exocyclic methylene grouping have been synthesized. These include substances with both regular and rearranged carbon frameworks. The X-ray structure of a rearranged α-methylene lactone shows that an earlier assignment of stereochemistry is incorrect and that this compound has an exceptionally distorted C=C-C=O unit. The methylene derivatives prepared have proved to have low cytoxicity.

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23

Buchanan, G. W., A. B. Driega, A. Moghimi, C. Bensimon, and K. Bourque. "cis-Cyclohexano-9-crown-3 ether. Solid state and low-temperature solution stereochemistry as determined by X-ray crystallography and nuclear magnetic resonance spectroscopy." Canadian Journal of Chemistry 71, no. 7 (1993): 951–59. http://dx.doi.org/10.1139/v93-127.

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The X-ray crystal structure of the title material has been determined at −130 °C. Low-temperature 1H1H COSY, 13C1H HETCOR, and DEPT 13C NMR spectra have been recorded, which permit unambiguous assignments of all carbon resonances when ring inversion is slow on the NMR timescale. The limiting low-temperature solution phase 13C spectrum has many common features with the solid phase 13C CPMAS spectrum recorded at 300 K. Spectra for the 7,10-tetra-deuterio derivative have also been obtained and substituent influences on 13C shieldings are discussed in detail.

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24

Koll, P., and J. Kopf. "Crystal and Molecular Structures of Penta-O-acetyl-aldehydo-D-glucose Dimethyl Acetal and of Hepta-O-acetyl-aldehydo-D-glucose Hydrate." Australian Journal of Chemistry 49, no. 3 (1996): 391. http://dx.doi.org/10.1071/ch9960391.

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The solid-state structures of the title compounds were determined by conventional single-crystal X-ray crystallography. In both cases a planar zigzag conformation of the carbon skeleton is observed with a resulting 1,3-parallel orientation of O(2) and O(4). In the case of the heptaacetate even a second such arrangement is established between O(3) and one of the oxygens at C(1). These findings substantiate the claim that such conformations are not as unfavourable as previously was assumed by many authors.

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25

Kicha, Alla A., Anatoly I. Kalinovsky, Alexander S. Antonov, et al. "Determination of C-23 Configuration in (20R)-23-Hydroxycholestane Side Chain of Steroid Compounds by 1H and 13C NMR Spectroscopy." Natural Product Communications 8, no. 9 (2013): 1934578X1300800. http://dx.doi.org/10.1177/1934578x1300800908.

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Epimeric (20 R,23 R)- and (20 R,23 S)-23-hydroxycholestane steroids were synthesized. Their structures were elucidated by extensive 1H and 13C NMR spectroscopy and application of the Mosher's method. All proton and carbon signals of the side chains were assigned. Based on these assignments spectral data allow the determination of the C-23 stereochemistry of (20 R)-23-hydroxycholestane side chains of the new natural steroids by comparison with spectra of the obtained model compounds. As a result, the C-23 configuration of two steroid compounds from the starfishes Lethasterias nanimensis chelife

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26

Dung, Duong Thi, Dan Thi Thuy Hang, Nguyen Xuan Nhiem, et al. "Rhabdaprovidines D–G, Four New 6,6,5-Tricyclic Terpenoids from the Vietnamese Sponge Rhabdastrella providentiae." Natural Product Communications 13, no. 10 (2018): 1934578X1801301. http://dx.doi.org/10.1177/1934578x1801301004.

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Four new 6,6,5-tricyclic terpenoids, named rhabdaprovidines D-G (1–4), were isolated from the Vietnamese sponge Rhabdastrella providentiae. The structures of 1–4 were elucidated by extensive analysis of HR-ESI-MS and NMR spectroscopy. The absolute stereochemistry of compounds 3 and 4 were determined by both experimental and theoretical calculated circular dichroism (CD) spectra. Compounds 1, 2, and 4 contained trans-syn-trans 6,6,5-tricyclic nucleus meanwhile compound 3 possessed trans-syn-cis ring junction. Compound 4 displayed novel structure by the presence of five rings and nine chiral car

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27

ANASTASIOU, D., E. M. CAMPI, H. CHAOUK, et al. "ChemInform Abstract: The Stereochemistry of Organometallic Compounds. Part 40. Rhodium- Catalyzed Reactions of Hydrogen and Carbon Monoxide with Alkenylanilines." ChemInform 25, no. 40 (2010): no. http://dx.doi.org/10.1002/chin.199440134.

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28

Kelpšas, Vinardas, Anna Leung, and Claes von Wachenfeldt. "Evolving Escherichia coli Host Strains for Efficient Deuterium Labeling of Recombinant Proteins Using Sodium Pyruvate-d3." International Journal of Molecular Sciences 22, no. 18 (2021): 9678. http://dx.doi.org/10.3390/ijms22189678.

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Labeling of proteins with deuterium (2H) is often necessary for structural biology techniques, such as neutron crystallography, NMR spectroscopy, and small-angle neutron scattering. Perdeuteration in which all protium (1H) atoms are replaced by deuterium is a costly process. Typically, expression hosts are grown in a defined medium with heavy water as the solvent, which is supplemented with a deuterated carbon source. Escherichia coli, which is the most widely used host for recombinant protein production, can utilize several compounds as a carbon source. Glycerol-d8 is often used as a carbon s

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29

Ciminiello, Patrizia, Ernesto Fattorusso, Silvana Magno, and Luciano Mayol. "New nitrogenous sesquiterpenes based on alloaromadendrane and epi-eudesmane skeletons from the marine sponge Axinellacannabina." Canadian Journal of Chemistry 65, no. 3 (1987): 518–22. http://dx.doi.org/10.1139/v87-090.

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Six new nitrogenous sesquiterpenes (1–6), which form two new isocyanide-isothiocyanate-formamide series, have been isolated from the marine sponge Axinellacannabina. The structure elucidation of these compounds is based upon spectral data, including 2D-nmr, and chemical interconversions. The complete assignment of all proton and carbon resonances in nmr spectra of axisonitrile-2 (7), an isonitrile previously isolated from the same source, is also reported, along with its complete relative stereochemistry.

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30

Brown, RFC, FW Eastwood, GD Fallon, SC Lee, and RP Mcgeary. "The Pyrolytic Rearrangement of 1-Alkynoyl-3-methylpyrazoles: Synthesis of Pyrazolo[1,5-a]pyridin-5-ols and Related Compounds." Australian Journal of Chemistry 47, no. 6 (1994): 991. http://dx.doi.org/10.1071/ch9940991.

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Flash vacuum pyrolysis of 1-(alkyn-2′-oyl)-3-methylpyrazoles at 650°/0.03 mm forms pyrazolo[1,5-a]pyridin-5-ols, often in high yield, which may bear substituents at C2, C3 or C7. In the absence of a 3-methyl group in the precursor, N-ethynylpyrazoles are formed in low yield. The formation of both types of product is interpreted as involving 3-(N-pyrazolyl)propadienones formed by N1 → N2 migration of the N-alkynoyl group with inversion of the three-carbon chain. The fused-ring structure of 2-methylpyrazolo[1,5-a]pyridin-5-ol (25) was established by X-ray crystallography of the O-benzoyl derivat

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31

Thomas, Santana A. L., Anthony Sanchez, Younghoon Kee, Nerida G. Wilson, and Bill J. Baker. "Bathyptilones: Terpenoids from an Antarctic Sea Pen, Anthoptilum grandiflorum (Verrill, 1879)." Marine Drugs 17, no. 9 (2019): 513. http://dx.doi.org/10.3390/md17090513.

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An Antarctic coral belonging to the order Pennatulacea, collected during the 2013 austral autumn by trawl from 662 to 944 m depth, has yielded three new briarane diterpenes, bathyptilone A-C (1–3) along with a trinorditerpene, enbepeanone A (4), which bears a new carbon skeleton. Structure elucidation was facilitated by one- and two-dimensional NMR spectroscopy, mass spectrometry and confirmed by X-ray crystallography. The three compounds were screened in four cancer cell lines. Bathyptilone A displayed selective nanomolar cytotoxicity against the neurogenic mammalian cell line Ntera-2.

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32

Endoma-Arias, Mary, Helen Dela Paz, and Tomas Hudlicky. "Chemoenzymatic Total Synthesis of (+)-10-Keto-Oxycodone from Phenethyl Acetate." Molecules 24, no. 19 (2019): 3477. http://dx.doi.org/10.3390/molecules24193477.

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The total synthesis of (+)-10-keto-oxycodone was attained from phenethyl acetate in a stereoselective manner. Absolute stereochemistry was established via enzymatic dihydroxylation of phenethyl acetate with the recombinant strain JM109 (pDTG601A) that furnished the corresponding cis-cyclohexadienediol whose configuration corresponds to the absolute stereochemistry of the ring C of (+)-10-keto-oxycodone. Intramolecular Heck reaction was utilized to establish the quaternary carbon at C-13, along with the dibenzodihydrofuran functionality. The C-14 hydroxyl and C-10 ketone were installed via SmI2

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33

Rocha, Kenneth, Jesus Magallon, Craig Reeves, et al. "Inhibition of Aminoglycoside 6′-N-acetyltransferase Type Ib (AAC(6′)-Ib): Structure–Activity Relationship of Substituted Pyrrolidine Pentamine Derivatives as Inhibitors." Biomedicines 9, no. 9 (2021): 1218. http://dx.doi.org/10.3390/biomedicines9091218.

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The aminoglycoside 6′-N-acetyltransferase type Ib (AAC(6′)-Ib) is a common cause of resistance to amikacin and other aminoglycosides in Gram-negatives. Utilization of mixture-based combinatorial libraries and application of the positional scanning strategy identified an inhibitor of AAC(6′)-Ib. This inhibitor’s chemical structure consists of a pyrrolidine pentamine scaffold substituted at four locations (R1, R3, R4, and R5). The substituents are two S-phenyl groups (R1 and R4), an S-hydroxymethyl group (R3), and a 3-phenylbutyl group (R5). Another location, R2, does not have a substitution, bu

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34

Campi, EM, WR Jackson, QJ Mccubbin, and AE Trnacek. "The Stereochemistry of Organometallic Compounds. XLIII. Rhodium-Catalysed Reactions of 2-(Alkenyloxy)benzylamines and 2-(N-Allyl-N-benzylamino)benzylamine." Australian Journal of Chemistry 49, no. 2 (1996): 219. http://dx.doi.org/10.1071/ch9960219.

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Reactions of 2-( allyloxy ) benzylamines with H2/CO in the presence of rhodium catalysts give 1,3-benzoxazines, and 2-(N- allyl-N-benzylamino ) benzylamine gives a quinazoline . These reactions have been shown to involve allylic cleavage followed by regioselective carbonylation at the internal carbon atom as demonstrated by crossover experiments. Reactions of longer chain ( alkenyloxy ) benzylamines under similar conditions give polymeric material.

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35

Monincová, Marta, Zbyněk Prokop, Jitka Vévodová, Yuji Nagata, and Jiří Damborský. "Weak Activity of Haloalkane Dehalogenase LinB with 1,2,3-Trichloropropane Revealed by X-Ray Crystallography and Microcalorimetry." Applied and Environmental Microbiology 73, no. 6 (2007): 2005–8. http://dx.doi.org/10.1128/aem.02416-06.

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ABSTRACT 1,2,3-Trichloropropane (TCP) is a highly toxic and recalcitrant compound. Haloalkane dehalogenases are bacterial enzymes that catalyze the cleavage of a carbon-halogen bond in a wide range of organic halogenated compounds. Haloalkane dehalogenase LinB from Sphingobium japonicum UT26 has, for a long time, been considered inactive with TCP, since the reaction cannot be easily detected by conventional analytical methods. Here we demonstrate detection of the weak activity (k cat = 0.005 s−1) of LinB with TCP using X-ray crystallography and microcalorimetry. This observation makes LinB a u

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36

Endoma-Arias, Mary Ann, Mariia Makarova, Helen Dela Paz, and Tomas Hudlicky. "Chemoenzymatic Total Synthesis of (+)-Oxycodone from Phenethyl Acetate." Synthesis 51, no. 01 (2018): 225–32. http://dx.doi.org/10.1055/s-0037-1611335.

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The stereoselective total synthesis of unnatural (+)-oxycodone from phenethyl acetate is described. Absolute stereochemistry was established via microbial dihydroxylation of phenethyl acetate with the recombinant strain JM109 (pDTG601A) to the corresponding cis-cyclohexadienediol whose configuration provides for the absolute stereochemistry of the ring C of (+)-oxycodone. Intramolecular Heck cyclization was employed to establish the quaternary carbon at C-13, along with the dibenzodihydrofuran functionality. The C-14 hydroxyl was installed via SmI2-mediated radical cyclization. The synthesi

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37

Kleszczyńska, Halina, Dorota Bonarska, Janusz Sarapuk, and Krzysztof Bielecki. "Physiological Activity of Some Organophosphorous Compounds and Their Influence on Mechanical Properties of Erythrocytes." Zeitschrift für Naturforschung C 56, no. 11-12 (2001): 999–1002. http://dx.doi.org/10.1515/znc-2001-11-1216.

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Abstract Hemolysis and fluidization of erythrocytes (RBC) membranes by some newly synthesized aminophosphonates as well as their potency to induce electrolyte efflux from cucumber (Cucumis sativus cv "Wisconsin") cotyledons were studied. Also, the chlorophyll content in aminophosphonate-treated cotyledons was affected. The compounds studied differed mainly in hydrophobicity of their substituents at the carbon, nitrogen and phosphorus atoms. It was found that aminophosphonate potency to fluidize RBC membranes depended on the combination of its overall lipophilicity and/or the kind of substitue

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38

Moser, Shasta, Ryan Church, M. Brad Peori, and Keith Vaughan. "Triazene derivatives of (1,x)-diazacycloalkanes. Part IV.1 Synthesis and characterization of 1-[2-aryl-1-diazenyl]-3-(3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinylmethyl)hexahydropyrimidines and 1-(5,5-dimethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinylmethyl)-5,5-dimethyl-3-[2-aryl-1-diazenyl]hexahydropyrimidines from the reaction of diazonium salts with mixtures of formaldehyde and 1,3-diaminopropanes." Canadian Journal of Chemistry 83, no. 8 (2005): 1071–83. http://dx.doi.org/10.1139/v05-131.

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Two new series of bistriazenes have been synthesized from a general reaction of diazonium salts with a mixture of a propanediamine and formaldehyde. Such reaction with 1,3-diaminopropane itself affords the 1-[2-aryl-1-diazenyl]-3-(3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinylmethyl)hexahydropyrimidines (6). 2,2-Dimethyl-1,3-diamino propane reacts in an analogous manner to give the 1-(5,5-dimethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinylmethyl)- 5,5-dimethyl-3-[2-aryl-1-diazenyl]hexahydropyrimidines (7). All new compounds have been characterized by IR and NMR spectroscopy, with elemental ana

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39

Tingley, Reid, M. Brad Peori, Ryan Church, and Keith Vaughan. "Triazene derivatives of (1,x)-diazacycloalkanes. Part V.1 Synthesis and characterization of 4-ethyl-3-({6-ethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinyl}methyl)-1-[2-aryl-1-diazenyl)hexa- hydropyrimidines from the reaction of diazonium salts with mixtures of formaldehyde and 1,3-diaminopentane." Canadian Journal of Chemistry 83, no. 10 (2005): 1799–807. http://dx.doi.org/10.1139/v05-192.

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A new series of bistriazenes has been synthesized from a general reaction of diazonium salts with a mixture of 1,3-diaminopentane (DYTEK® EP diamine) and formaldehyde, which affords the 4-ethyl-3-({6-ethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinyl}methyl)-1-[2-aryl-1-diazenyl]hexahydropyrimidines (1). Each of the molecules of type 1 is built up of two equivalent 3-(aryldiazenyl)-6-ethylhexahydro-1-pyrimidinyl groups attached to a central methylene group. The importance of this study is in part due to the fact that the formaldehyde1,3-diaminopentane system has not previously been investigat

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40

Kuznetsov, Valerij. "Stereochemistry of Simple Molecules inside Nanotubes and Fullerenes: Unusual Behavior of Usual Systems." Molecules 25, no. 10 (2020): 2437. http://dx.doi.org/10.3390/molecules25102437.

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Over the past three decades, carbon nanotubes and fullerenes have become remarkable objects for starting the implementation of new models and technologies in different branches of science. To a great extent, this is defined by the unique electronic and spatial properties of nanocavities due to the ramified π-electron systems. This provides an opportunity for the formation of endohedral complexes containing non-covalently bonded atoms or molecules inside fullerenes and nanotubes. The guest species are exposed to the force field of the nanocavity, which can be described as a combination of elect

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41

Arnaud, R., S. Choubani, R. Subra, M. Vidal, M. Vincens, and V. Barone. "Le radical méthylènecyclopropyle: étude théorique. Chloration par t-BuOCl et réduction par (nBu)3SnH de dérivés cyclopropéniques." Canadian Journal of Chemistry 63, no. 9 (1985): 2511–21. http://dx.doi.org/10.1139/v85-416.

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The allylic chlorination of ethyl 2,3-dialkyl 2-cyclopropenecarboxylate or primary and tertiary alcohols is highly regio- and stereoselective. The halogenated methylenecyclopropane derivative only is observed. In that compound, the halogen substituent and the functional group are in a trans position with respect to the ring. The halogenated allylic compounds of methylenecyclopropane and of cyclopropene undergo reduction by (nBu)3SnH with the same stereochemistry. Products arising from ring opening are also observed. The exocyclic migration of the double bond can be related to the formation of

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42

Liu, Hui, and B. Mario Pinto. "Design and synthesis of selenonium and sulfonium ions related to the naturally occurring glucosidase inhibitor salacinol." Canadian Journal of Chemistry 84, no. 10 (2006): 1351–62. http://dx.doi.org/10.1139/v06-100.

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Four series of analogues of the naturally occurring glucosidase inhibitor salacinol were synthesized for structure–activity studies with different glycosidase enzymes. The target zwitterionic compounds were synthesized by means of nucleophilic attack at the least-hindered carbon atom of the 1,3-cyclic sulfates derived from D-glucose and D-mannose by the isopropylidene-protected 1,4-anhydro-4-thio- and seleno-D-allitols and the 4-thio- and seleno-L-allitols. Deprotection of the coupled products afforded the novel sulfonium and selenonium ions containing polyhy droxylated acyclic chains of four

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43

García-Granados, A., A. Martínez, M. E. Onorato, and J. Santoro. "Substituent effects on carbon-13 chemical shifts and the stereochemistry ofent-beyeranic andent-beyer-15-enic compounds substituted on the bicyclo[3.2.1]octane moiety." Magnetic Resonance in Chemistry 24, no. 10 (1986): 853–61. http://dx.doi.org/10.1002/mrc.1260241003.

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44

Tingley, Reid, and Keith Vaughan. "Triazene derivatives of (1,x)-diazacycloalkanes. Part VII. Synthesis of a series of 1-aryl-2-[3-(3-[2-aryl-1-diazenyl]-1,3-diazepan-1-ylmethyl)-1,3-diazepan-1-yl]-1-diazenes from the reaction of diazonium salts with mixtures of formaldehyde and 1,4-diaminobutane." Canadian Journal of Chemistry 84, no. 10 (2006): 1434–41. http://dx.doi.org/10.1139/v06-123.

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A new series of bistriazenes, the 1-aryl-2-[3-(3-[2-aryl-1-diazenyl]-1,3-diazepan-1-ylmethyl)-1,3-diazepan-1-yl]-1-diazenes (8), has been synthesized from the reaction of diazonium salts with a mixture of 1,4-diaminobutane and formaldehyde. All new compounds of series 8 have been characterized by IR and NMR spectroscopy, and the elemental composition of selected examples has been verified by elemental analysis. The connectivity of the series has been unequivocally determined by X-ray crystallography. The new bistriazenes are important because the structure contains the novel saturated heterocy

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45

Garza-Ortiz, Ariadna, Carlos Camacho-Camacho, Teresita Sainz-Espuñes, et al. "Novel Organotin(IV) Schiff Base Complexes with Histidine Derivatives: Synthesis, Characterization, and Biological Activity." Bioinorganic Chemistry and Applications 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/502713.

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Five novel tin Schiff base complexes with histidine analogues (derived from the condensation reaction between L-histidine and 3,5-di-tert-butyl-2-hydroxybenzaldehyde) have been synthesized and characterized. Characterization has been completed by IR and high-resolution mass spectroscopy, 1D and 2D solution NMR (1H,13C and119Sn), as well as solid state119Sn NMR. The spectroscopic evidence shows two types of structures: a trigonal bipyramidal stereochemistry with the tin atom coordinated to five donating atoms (two oxygen atoms, one nitrogen atom, and two carbon atoms belonging to the alkyl moie

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46

Thomson, RJ, WR Jackson, D. Haarburger, EI Klabunovsky, and VA Pavlov. "The Stereochemistry of Organometallic Compounds. XXIX. Synthesis of Steroidal 1,4-Diphosphine, 1,3-Diphosphine and 1,6-Diphosphine and Their Evaluation as Ligands in Metal Catalyzed Asymmetric Synthesis." Australian Journal of Chemistry 40, no. 6 (1987): 1083. http://dx.doi.org/10.1071/ch9871083.

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The steroidal 1,4-diphosphines 3α- and 3β-diphenylphosphino-2a-(2'-diphenylphosphinoethyl)-5α-cholestanes and their 5H-benzo[b] phosphindole derivatives have been prepared and shown to be useful ligands in asymmetric hydrogenation reactions. Interestingly the 3α- and 3β-derivatives lead to opposing enantioselection preferences when used in these reactions. A steroidal 1,3-diphosphine, 3α-diphenylphosphino-2α-diphenylphosphinomethyl-5α-cholestane, has been prepared as a mixture containing some of the 3β-epimer. The 3α-1,3-diphosphine led to similar enantioselection in hydrogenation reactions as

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47

Vaughan, Keith, Shasta Lee Moser, Reid Tingley, M. Brad Peori, and Valerio Bertolasi. "Triazene derivatives of (1,x-)diazacycloalkanes. Part VI. 3-({5,5-Dimethyl-3-[2-aryl-1-diazenyl]-1-imidazolidinyl}methyl)-4,4-dimethyl-1-[2-aryl-1-diazenyl]imidazolidines — Synthesis, characterization, and X-ray crystal structure." Canadian Journal of Chemistry 84, no. 10 (2006): 1294–300. http://dx.doi.org/10.1139/v06-091.

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Reaction of a series of diazonium salts with a mixture of formaldehyde and 1,2-diamino-2-methylpropane affords the 3-({5,5-dimethyl-3-[2-aryl-1-diazenyl]-1-imidazolidinyl}methyl)-4,4-dimethyl-1-[2-aryl-1-diazenyl]imidazolidines (1a–1f) in excellent yield. The products have been characterized by IR and NMR spectroscopic analysis, elemental analysis, and X-ray crystallography. The X-ray crystal structure of the p-methoxycarbonyl derivative (1c) establishes without question the connectivity of these novel molecules, which can be described as linear bicyclic oligomers with two imidazolidinyl group

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48

Varney, Michelle L., Daniel B. Goetz, David F. Wiemer, and Sarah A. Holstein. "Isoprenoid Amide Bisphosphonates As a Novel Class of Geranylgeranyl Diphosphate Synthase Inhibitors." Blood 132, Supplement 1 (2018): 4679. http://dx.doi.org/10.1182/blood-2018-99-112965.

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Abstract Multiple myeloma is characterized by the production of monoclonal protein by clonal plasma cells and is a malignancy inherently susceptible to agents that disrupt protein homeostasis. We have previously demonstrated that targeting the geranylgeranylation of Rab GTPases is a novel mechanism by which to induce myeloma cell apoptosis via disruption of intracellular monoclonal protein trafficking and induction of the unfolded protein response pathway. Our previous efforts have focused on the development of novel triazole isoprenoid bisphosphonates as inhibitors of the enzyme geranylgerany

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Rocha, Rênica Alves de Morais, Thaís Forest Giacomello, Antonio Maia de Jesus Chaves Neto, Gunar Vingre Da Silva Mota, and Fabio Luiz Paranhos Costa. "Carbon-13 Nuclear Magnetic Resonance Chemical Shift Calculation Protocol Applied to Rigid Triterpenes Molecules." Advanced Science, Engineering and Medicine 12, no. 8 (2020): 995–1001. http://dx.doi.org/10.1166/asem.2020.2636.

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Nuclear magnetic resonance spectroscopy is one of the most powerful experimental techniques for obtaining three-dimensional structures of complex molecules, mainly for the analysis of the relative and absolute configurations of organic compounds. For this reason, this has become one of the most promising tools in the field of chemistry. From the theoretical point of view, advanced computational protocols have been developed for calculating nuclear magnetic resonance, mainly hydrogen-1 and carbon-13, parameters of isolated molecules, in which the environmental effects are neglected. These effec

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Fraser, Robert R., Corinne Bensimon, Neil C. Faibish та Fanzuo Kong. "An X-ray and conformational study of the α-chloro derivatives of 5,7-dihydro-1,11-dimethyl-6H-dibenzo[a,c]cyclohepten-6-one". Canadian Journal of Chemistry 72, № 6 (1994): 1481–88. http://dx.doi.org/10.1139/v94-184.

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The crystal structures for four α-chloro derivatives 2–5 of the titled ketone 1 have been determined, confirming their earlier assignments of stereochemistry. Variations in the conformations of 2–5 suggested some flexibility in the central seven-membered ring. Molecular mechanics calculations of the changes in energy as a function of the internal torsional angles at the carbonyl of these chloro derivatives indicated the ring flexibility to be comparable to that of cyclohexanone. In the three compounds containing an axial chlorine the distance between the chlorine atom and two of the carbon ato

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