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Journal articles on the topic 'Dimethyl Acetal'

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Published: 4 June 2021

Last updated: 1 February 2022

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1

Graikou, Konstantia, Nektarios Aligiannis, Ioanna B. Chinou, and Catherine Harvala. "Cantleyoside-dimethyl-acetal and Other Iridoid Glucosides from Pterocephalus perennis – Antimicrobial Activities." Zeitschrift für Naturforschung C 57, no. 1-2 (February 1, 2002): 95–99. http://dx.doi.org/10.1515/znc-2002-1-217.

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Cantleyoside-dimethyl-acetal (6), was isolated from the endemic Greek plant Pterocephalus perennis subsp. perennis in addition to five other known iridoid glucosides, loganin, loganic acid, cantleyoside, secologanin, and secologanin-dimethyl-acetal. The structure of these compounds was determined by all spectroscopic means mainly by NMR and MS techniques. The above compounds as well as their acetyl derivatives were tested against six Gram positive and negative bacteria and three pathogenic fungi.

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2

Kaiho, Atsushi, Makiko Kogo, Ryo Sakai, Kaori Saito, and Takashi Watanabe. "In situ trapping of enol intermediates with alcohol during acid-catalysed de-polymerisation of lignin in a nonpolar solvent." Green Chemistry 17, no. 5 (2015): 2780–83. http://dx.doi.org/10.1039/c5gc00130g.

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3

Kidjemet. "N,N-Dimethylformamide Dimethyl Acetal." Synlett, no. 10 (2002): 1741–42. http://dx.doi.org/10.1055/s-2002-34251.

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4

Collins, DJ, LM Downes, and M. Kyriakou. "Enolic Ortho Esters. III. Preparation of a Keto Acetal by Hydride Reduction of an Enolic Ortho Ester." Australian Journal of Chemistry 42, no. 9 (1989): 1617. http://dx.doi.org/10.1071/ch9891617.

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Lithium aluminium hydride reduction of the enolic ortho ester 4′,4′-dimethyl-3,4,5,8-tetra-hydrospiro [2H-l-benzopyran-2,21-[1,3]dioxolan] (8) in the absence of solvent gave 6-[21-(4″,4″- dimethyl-1″,3″-dioxolan-2″-yl)ethyl]cyclohex-3-en-1-one (11) which was isomerized to the α'β-unsaturated keto acetal (10). Similarly, hydride reduction of the phenolic ortho ester 4′-methyl-3,4-dihydrospiro[2H-1-benzopyran-2,2′-[1,3]dioxolan] (12a) and the 4′,4′-dimethyl analogue (12b), afforded the corresponding phenolic acetals (14a) and (14b) respectively, in high yields.′

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5

Al-Saleh, Balkis, Nouria Al-Awadi, Halema Al-kandari, Mervat Mohammed Abdel-Khalik, and Mohamed Hilmy Elnagdi. "Studies with 2H pyranones: Synthesis of new 3-substituted-4-hydroxy-2H-pyran-2-ones." Journal of Chemical Research 2000, no. 1 (January 2000): 16–17. http://dx.doi.org/10.3184/030823400103165725.

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3-Acetyl-4-hydroxy-6-methyl-2H-pyran-2-one 1a condensed with N,N-dimethylformamide dimethyl acetal yielding the enaminone 3a. The latter reacted with a variety of reagents affording pyridine derivatives 11, benzofuranoylpyranes 14 and 17, pyranylpyranes 22, pyranylpyrazole 29a,b and pyranylisoxazole 33.

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6

Lamba, Doriano, Cenydd Burden, William Mackie, and Bernard Sheldrick. "The crystal and molecular structure of hexa-O-acetyl-carrabiose dimethyl acetal." Carbohydrate Research 155 (November 1986): 11–17. http://dx.doi.org/10.1016/s0008-6215(00)90129-0.

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7

Mishra, Subhajit, Sougata Santra, and Alakananda Hajra. "Ligand-free reusable nano copper oxide-catalyzed synthesis of 3-amino-1,4-diynes." RSC Advances 5, no. 111 (2015): 91326–29. http://dx.doi.org/10.1039/c5ra18350b.

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The synthesis of 3-amino-1,4-diynes has been developed by the two-component coupling of N,N-dimethyl formamide dimethyl acetal with terminal alkynes using CuO nanoparticles as an efficient catalyst under mild reaction conditions.

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8

Hlavatý, Jaromír, and Miroslav Polášek. "Electrochemical Preparation of Alkynedial Tetramethyl Acetals." Collection of Czechoslovak Chemical Communications 73, no. 1 (2008): 19–23. http://dx.doi.org/10.1135/cccc20080019.

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Tetramethyl acetals of alkynedials were prepared by anodic oxidation of corresponding alkyne-1,ω-diols (C4 and C6) in trimethyl orthoformate on glassy carbone anode in 80% yield. 1,1,4,4-Tetramethoxybut-2-yne (2a) can be prepared by this one-step procedure from but-2-yne-1,4-diol (1a) instead of a multistep chemical procedure starting from 2,5-dimethoxyfuran. Propargyl alcohol (3) can be similarly anodically oxidized in trimethyl orthoformate giving dimethyl acetal of propynal (4) in 85% yield.

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9

Groß, Hans, and Burkhard Costisella. "Zur Umsetzung von Dimethylformamid-dimethyl-acetal mit Phosphortrichlorid." Zeitschrift für Chemie 10, no. 10 (September 1, 2010): 404–5. http://dx.doi.org/10.1002/zfch.19700101024.

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10

Kantlehner, Willi, Erwin Haug, and Christophe Bauer. "Orthoamide und Iminiumsalze, LXXXI [1]. Orthoamid-Derivate der 1,3-Dimethylparabansäure / Orthoamides and Iminium Salts LXXXI [1]. Orthoamide Derivatives of 1,3-Dimethylparabanic Acid." Zeitschrift für Naturforschung B 67, no. 9 (September 1, 2012): 907–12. http://dx.doi.org/10.5560/znb.2012-0123.

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1,3-Dimethyl-5-imino-imidazolidine-2,4-dione (7a) undergoes thiolysis (H2S) to give the corresponding imidazolidine-2,4-dione-5-thione derivative 6. The 5-N-methylimino analogue 7b can be obtained from 7a by methylation. Further methylation of 7b affords the crude iminium salt 8c from which the heterocyclic orthoamide derivatives 10, 11 can be prepared. The heterocyclic amide acetal 9a can be obtained from 7a and dimethyl sulfate in methanol and subsequent addition of sodium methanolate in a one-pot reaction. The aminal ester 10 is converted to the amide acetal 9a on treatment with hydrogen chloride in methanol

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11

Yakovleva, Marina P. "Low-temperature reduction of acyclic carvomentholactone derivatives with diisobutylaluminum hydride in methylene chloride." Butlerov Communications 61, no. 2 (February 29, 2020): 24–28. http://dx.doi.org/10.37952/roi-jbc-01/20-61-2-24.

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Earlier, we discovered a novel reaction in the chemistry of organoaluminum compounds - the formation of O-isobutyl acetals during low-temperature (-70 °С) treatment of a number of seven-membered lactones with a twofold (or more) molar amount of diisobutylaluminium hydride in methylene chloride. In addition, it was shown that the acyclic derivatives of (-)-mentholactone - methyl 6-hydroxy-3,7-dimethyl-octanoate and its 6-oxo analogue - also enter into the low-temperature reduction reaction of diisobutylaluminum hydride in methylene chloride. Moreover, methyl 6-hydroxy-3,7-dimethyloctanoate in this reaction behaves similarly to (-)-mentholactone: when 4 equivalents of diisobutylaluminium hydride acts on it, the reaction proceeds with the predominant formation of isobutyl acetal as the only (2S,7S)-epimer. Methyl 6-oxo-3,7-dimethyl octanoate in a low-temperature reduction reaction with 4 equivalents of diisobutylaluminium hydride in methylene chloride acts as a mixture of (-)-mentholactone and isomentolactone, leading to a mixture of (2S,7S)-, (2S,7R)- and (2R,7R)-isobutyl acetals in a ratio of 3.2: 1.3: 1.0, respectively. In the present work, when low-temperature reduction was involved in the reaction with diisobutylaluminium hydride, methyl (3R)-6-hydroxy- or (3R)-6-oxo-3-isopropylheptanoates available from carvomentolactone reacted without the formation of isobutyl acetal: a mixture of (2: 1) 6-hydroxy-(3R)-isopropylheptanal and (4R)-isopropyl-7-methyloxepan-2-ol was obtained.

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12

Kasum, B., and RH Prager. "Reactions of Some 3-Methylcyclohexenones With Dimethylformamide Dimethyl Acetal." Australian Journal of Chemistry 43, no. 1 (1990): 63. http://dx.doi.org/10.1071/ch9900063.

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The reactions of 3-methylcyclohexenone, 4-ethoxycarbonyl-3-methylcyclohexenone, isophorone, 2-amino-3-methylcyclohexenone and 2-nitro-3-methylcyclohexenone with dimethylform-amide dimethyl acetal have been investigated, and the products characterized.

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13

Ferroni, Edward L., Victoria DiTella, Nancy Ghanayem, Rebecca Jeske, Christopher Jodlowski, Matthew O'Connell, Jennifer Styrsky, Robyn Svoboda, Ajay Venkataraman, and Beth M. Winkler. "A Three-Step Preparation of Dihydroxyacetone Phosphate Dimethyl Acetal†." Journal of Organic Chemistry 64, no. 13 (June 1999): 4943–45. http://dx.doi.org/10.1021/jo9823902.

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14

Ali, Muhammad Shaiq, James R. Hanson, and Viqar Uddin Ahmad. "The Estenfication of Gibberellins with Dimethylformamide Dimethyl Acetal (DMFDMA)." Zeitschrift für Naturforschung B 52, no. 10 (October 1, 1997): 1237–44. http://dx.doi.org/10.1515/znb-1997-1015.

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The key step is to prepare rare gibberellins by converting the more readily available gibberellins (GA3, GA4, GA7 and GA13) into their m ethyl esters. The DMFDMA is employed as an esterifying reagent to avoid the diazom ethane due to its toxic, explosive and hazardous nature. It is observed that DMFDMA apart from esterification can also be used as acetylating and epimerizing reagent.

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15

Guthrie, J. Peter, Jonathan Barker, Patricia A. Cullimore, Jinqiao Lu, and David C. Pike. "The tetrahedral intermediate from the hydration of N-methylformanilide." Canadian Journal of Chemistry 71, no. 12 (December 1, 1993): 2109–22. http://dx.doi.org/10.1139/v93-262.

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Heats of hydrolysis of N-methylformanilide dimethyl acetal have been measured in basic solution. The heat of formation of N-methylformanilide was obtained by determining the equilibrium constant in aqueous solution for its formation from formic acid and N-methylaniline as a function of temperature:[Formula: see text]. These data permit the calculation of the heat of formation of N-methylformanilide dimethyl acetal, [Formula: see text]. The free energy of formation of the tetrahedral intermediate in the hydrolysis of N-methylformanilide was calculated by methods we have previously reported. Consideration of the energetics of the intermediates and the known rates of reaction leads to the conclusion that the rate-determining step for alkaline hydrolysis is cleavage of the C—N bond.

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16

Šinkovec, Rok, Uroš Grošelj, Benjamin Prek, Marta Počkaj, Sebastijan Ričko, Jurij Svete, and Branko Stanovnik. "A simple synthesis of dimethyl 2-[(Z)-3-amino-1-oxo-1-(substituted)but-2-en-2-yl]fumarates: potential intermediates in the synthesis of polysubstituted five- and six-membered heterocycles." Zeitschrift für Naturforschung B 71, no. 6 (June 1, 2016): 677–82. http://dx.doi.org/10.1515/znb-2016-0017.

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AbstractIn this communication, a simple synthesis of dimethyl 2-[(Z)-3-amino-1-oxo-1-(substituted)but-2-en-2-yl]fumarates is described. Methyl ketones were transformed by treatment with N,N-dimethylacetamide dimethyl acetal (DMADMA) into 3-dimethylamino-1-(substituted)but-2-en-1-ones, followed by treatment with ammonium acetate into (Z)-3-amino-1-(substituted)but-2-en-1-ones and addition to dimethyl acetylenedicarboxylate. These novel polysubstituted butadienes are potential intermediates for the metal-free preparation of polysubstituted five- and six-membered heterocycles.

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17

Veselý, Ivan, and Václav Dědek. "Reactivity of 2,2-difluoro-3-methyl-3-butenal toward some O-, N- and C-nucleophiles." Collection of Czechoslovak Chemical Communications 50, no. 12 (1985): 2730–42. http://dx.doi.org/10.1135/cccc19852730.

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Addition of nucleophiles to 2,2-difluoro-3-methyl-3-butenal (I) is complicated by its spontaneous polymerization. Compound I afforded neither hydrate nor dimethyl acetal but reacted with ethylene glycol to give the cyclic acetal II. Reaction with acetyl chloride and acetic anhydride led to the respective acetate III and diacetate IV. Satisfactory reaction with N-nucleophiles was observed only in the case of hydroxylamine and dinitrophenylhydrazine. Diethylamine reacted with I only at 150 °C to give the reduction product VI and the ethylaldimine VII. The compound I added nitromethane and sodium cyanide (giving X and XI, respectively); the adducts or products of their reduction with lithium aluminium hydride were hydroxylated at the double bond to give analogues of alcoholic sugars with difluoromethylene group in position 3. Hydroxylation of the butenal I or the acetate III afforded 3,3-difluoro-2,4-dihydroxy-4-methyloxolane (XIX) which was prepared also by cleavage of the acetal XVIII obtained from II by hydroxylation. Addition of bromine to the double bond in III and IV gave the dibromo derivatives XV and XVI; the attempted replacement of bromine in XV and XVI by acetate anion failed. Bromination of I in aqueous medium afforded 3-bromo-2,2-difluoro-3-methyl-4-butanolide (XIV).

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18

Kasum, B., RH Prager, and C. Tsopelas. "Dihydroindol-7(6H)-ones and 6,7-Dihydropyrrolo[2,3-c]azepine-4,8(1H,5H)-dione." Australian Journal of Chemistry 43, no. 2 (1990): 355. http://dx.doi.org/10.1071/ch9900355.

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3-Methylcyclohexenones may be converted into dihydroindol-7(6H)-ones by conversion of the epoxide into the 2-benzylamino-3-methylcyclohexenone, which reacts with dimethyl- formamide dimethyl acetal to give N-benzyldihydroindol-7(6H)-ones. The limitations of the process are discussed, as is the failure to convert the dihydroindol-7(6H)-ones into dihydropyrroloazepinediones by Beckmann or Schmidt rearrangements. An example of the latter compounds was made by a simple procedure from pyrrolecarboxylic acid.

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19

Brien, M., L. Berthiaume, I. Rudkowska, P. Julien, and J. F. Bilodeau. "Placental dimethyl acetal fatty acid derivatives are elevated in preeclampsia." Placenta 51 (March 2017): 82–88. http://dx.doi.org/10.1016/j.placenta.2017.01.129.

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20

Burilov, Alexander R., Almir S. Gazizov, Yulia M. Volodina, Michael A. Pudovik, Wolf D. Habicher, Ingmar Bauer, Aidar T. Gubaidullin, Igor A. Litvinova, and Alexander I. Konovalov. "Unusual reactions of resorcinol and methylresorcinol with methylaminoacetaldehyde dimethyl acetal." Mendeleev Communications 15, no. 4 (January 2005): 153–54. http://dx.doi.org/10.1070/mc2005v015n04abeh002103.

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21

Abu-Shanab, Fathi A., Sherif M. Sherif, and Sayed A. S. Mousa. "Dimethylformamide dimethyl acetal as a building block in heterocyclic synthesis." Journal of Heterocyclic Chemistry 46, no. 5 (September 2009): 801–27. http://dx.doi.org/10.1002/jhet.69.

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22

VARTANYAN, M. M., A. V. KHANDIN, L. YU BREZHNEV, and R. A. KARAKHANOV. "ChemInform Abstract: Synthesis of 5-Methoxytetrahydrofuran-3-carboxaldehyde Dimethyl Acetal." ChemInform 23, no. 15 (August 22, 2010): no. http://dx.doi.org/10.1002/chin.199215162.

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23

Sun, Yue-Wei, Yue-Ming Bei, and Lan-Zhi Wang. "A catalyst-free four-component domino reaction for the synthesis of functionalized 3-acyl-1,5-benzodiazepines." Organic & Biomolecular Chemistry 17, no. 4 (2019): 930–38. http://dx.doi.org/10.1039/c8ob02903b.

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Various functional 3-acyl-1,5-benzodiazepines were synthesized via a catalyst-free four-component domino reaction. A total of 26 examples were examined by reacting inexpensive starting materials of N,N-dimethylformamide dimethyl acetal, aromatic ketones, 1,2-phenylenediamine compounds and aldehyde derivatives in high yields.

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24

Heard, Peter J., Alex D. Bain, and Paul Hazendonk. "Stereochemical rearrangements in tricarbonylrhenium(I) halide complexes of the nonracemic chiral ligand 2-[(4R,5R)-dimethyl-1,3-dioxan-2-yl]pyridine (L): a dynamic NMR study." Canadian Journal of Chemistry 77, no. 11 (November 1, 1999): 1707–15. http://dx.doi.org/10.1139/v99-152.

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Tricarbonylrhenium(I) halide complexes of the nonracemic chiral ligand 2-[(4R,5R)-dimethyl-1,3-dioxan-2-yl]pyridine (L), namely fac-[ReX(CO)3L] (X = Cl, Br, or I), have been prepared and their latent fluxionality studied by dynamic NMR techniques in the slow and intermediate exchange regimes. In solution, these complexes give rise to four diastereoisomers, depending on the configuration at the metal and at the acetal-carbon atom, respectively; the relative populations are in the order SR > RR >>; RS > SS. At moderate temperatures, a reversible "acetal ring flip" leads to formal inversion of configuration at the acetal-carbon atom; the free energies of activation are in the range 84-88 kJ mol-1 at 298 K. Above ca. 370 K, reversible ligand dissociation also occurs, leading to an exchange of all four diastereoisomers on the NMR chemical shift time-scale.Key words: dynamic NMR, fluxionality, tricarbonylrhenium(I) complexes, chiral acetal ligands.

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25

Collins, DJ, JD Cullen, and GM Stone. "The Structure and Function of Estrogens .10. Synthesis of 5,5-Dimethyl-Cis-4b,5,6,10b,11,12-Hexahydrochrysene-2,8-Diol - the Estrogenic Activity of This and of Related C-Methylated Hydrochrysenediols." Australian Journal of Chemistry 41, no. 5 (1988): 745. http://dx.doi.org/10.1071/ch9880745.

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Reaction of 6-methoxy-2-(p- methoxyphenyl )-3,4-dihydronaphthalen-1(2H)- one (9) with dimethylketene ethyl trimethylsilyl acetal (10) in the presence of titanium tetrachloride gave ethyl 2-methyl-2-[6?-methoxy- 2?-(p- methoxyphenyl )-3?,4?-dihydronaphthalen-1?-yl] propanoate (11) which upon treatment with methanesulfonic acid afforded the lactone (13). Reduction of (11) with lithium/ammonia yielded mainly 6-methoxy- 2-(p- methoxyphenyl )-1,2,3,4-tetrahydronaphthalene (16), but hydrogenation of (11) over palladium/charcoal gave 61% of ethyl (1?RS,2?RS)-2-methyl-2-[6?-methoxy-2?-(p- methoxyphenyl )-1?,2?,3?,4?- (tetrahydronaphthalen-1?-yl] propanoate (21a). Alternatively, the ester (21a) was prepared in three steps from the ketone (9) by reaction of the derived 1ξ-acetoxy-6-methoxy-2ξ-(p- methoxyphenyl )-1,2,3,4- tetrahydronaphthalene (20b) with the ketene silyl acetal (10) in the presence of zinc iodide. Treatment of the ester (21a) with methanesulfonic acid afforded 72% of 2,8-dimethoxy-5,5-dimethyl-cis-4b, 10b,11,12-tetrahydrochrysen-6(5H)-one (22) which was converted into 2,8-dimethoxy-5,5-dimethyl-cis-4b,5,6,10b,11,12-hexahydrochrysene (23) in 63% yield via the dithiolan (24). Demethylation of (23) gave 5,5- dimethyl-cis-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol (3a). �� Assays of the oestrogenic activity of compound (3a), and of related hydrochrysenediols are reported.

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26

Bezenšek, Jure, Benjamin Prek, Uroš Grošelj, Amalija Golobič, Katarina Stare, Jurij Svete, Willi Kantlehner, Gerhard Maas, and Branko Stanovnik. "A Simple Metal-free Synthesis of 2,4,5-Trisubstituted Pyridines and Pyridine N-Oxides by [2+2] Cycloaddition of Enaminones to Propyne Iminium Salts." Zeitschrift für Naturforschung B 69, no. 5 (May 1, 2014): 554–66. http://dx.doi.org/10.5560/znb.2014-4021.

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Herein a simple one-pot metal-free synthesis of 2,4,5-trisubstituted pyridines and pyridine Noxides by [2+2] cycloaddition of enaminones, which are prepared in situ from alkyl, aryl and heteroaryl methyl ketones using N,N-dimethylformamide dimethyl acetal (DMFDMA), and propyne iminium salts as electron-poor acetylenes, is described.

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27

Lu, Xiaosong, Darren L. Reid, and John Warkentin. "Diaryloxycarbenes from oxadiazolines." Canadian Journal of Chemistry 79, no. 3 (March 1, 2001): 319–27. http://dx.doi.org/10.1139/v01-016.

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Symmetric and unsymmetric 2,2-diaryloxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines were synthesized by oxidative cyclization of aryloxycarbonyl hydrazones of acetone with lead tetraacetate and subsequent treatment of the product mixture with a phenol in acidic solution. Thermolysis of the oxadiazolines in benzene solution at 110°C afforded carbonyl ylide intermediates that cyclize, in part, to the corresponding 2,2-diaryloxyoxirane intermediates. The oxiranes, which were not observed, are required to account for the 1,1-diaryloxy-2-methylpropenes (ketene acetals) that were isolated. Most of the carbonyl ylides fragment to acetone and diaryloxycarbenes. The latter form dimers (tetraaryloxyethenes) or they can be trapped with phenols to form orthoformates. Diphenoxycarbene was also trapped with dimethyl acetylenedicarboxylate (DMAD). The method appears to be the first for generating the parent diphenoxycarbene under relatively mild conditions in solution, and the only one to date for generating unsymmetrically substituted diaryloxycarbenes. Minor competing fragmentations of the oxadiazolines to 2-diazopropane and the appropriate diaryl carbonates, were also observed.Key words: diarylcarbonate, diaryloxycarbene, diaryloxy oxadiazoline, ketene acetal, orthoformate.

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28

Reyes, Efraim, Jose L. Vicario, Dolores Badía, and Luisa Carrillo. "Organocatalytic Asymmetric Michael Addition of Aldehydes to β-Nitroacroleine Dimethyl Acetal." Organic Letters 8, no. 26 (December 2006): 6135–38. http://dx.doi.org/10.1021/ol062627d.

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29

Altıokka, Mehmet R., and Halit L. Hoşgün. "Kinetics of Hydrolysis of Benzaldehyde Dimethyl Acetal over Amberlite IR-120." Industrial & Engineering Chemistry Research 46, no. 4 (February 2007): 1058–62. http://dx.doi.org/10.1021/ie060716o.

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30

García, Alberto, Luis Castedo, and Domingo Domínguez. "A New Method for theN-Benzylation ofN-Tosyl Aminoacetaldehyde Dimethyl Acetal." Synlett 1993, no. 04 (1993): 271–72. http://dx.doi.org/10.1055/s-1993-22427.

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31

Collins, DJ, and SB Rutschmann. "Enolic Ortho Esters. II. Tandem Nucleophilic Electrophilic Dimethylation of 4',4'-Dimethyl-3,4,5,8-tetrahydrospiro[2H-1-Benzopyran-2,2'-[1,3]dioxolan]." Australian Journal of Chemistry 42, no. 9 (1989): 1447. http://dx.doi.org/10.1071/ch9891447.

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Reaction of 4′,4′-dimethyl-3,4,5,8-tetrahydrospiro[2H-1-benzopyran-2,2′-[l,3]dioxolan](9) with methylmagnesium iodide in benzene or toluene at 40� gave the iodomagnesium enolate acetal (10) which upon in situ reaction with methyl iodide afforded 56% of pure 6 ξ-methyl- 6-[2′-(2″,4″,4″-trimethyl-1″,3″-dioxolan 2″yl)ethyl]cyclohex-3-en-one (11), the product of tandem nucleophilic/electrophilic dimethylation . Aqueous ammonium chloride workup of the iodomagnesium enolate (10) gave 6-[2′-(2″,4″,4″-trimethyl-1″,3″-dioxolan 2″yl)ethyl] cyclohex-3-en-1-one (7). Some further transformations of the methylated keto acetal (11) are described.

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32

Hanaya, Tadashi, Kiyoshi Torigoe, Kazuyuki Soranaka, Horoshi Yamamoto, Yao Qizhengt, and Wolfgang Pfleiderer. "Pteridines CV." Pteridines 6, no. 1 (February 1995): 1–7. http://dx.doi.org/10.1515/pteridines.1995.6.1.1.

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Summary Treatment of L-biopterin (I) with N,N-dimethyformamide dimethyl- (or diethyl)acetal and then with acetic anhydride in pyridine gave 1',2'-di-O-acetyl-N'-(N,N-dimethylaminomethylene)-L-biopterin (4), which was converted by the Mitsunobu reaction into 3-methyl (5) and 3-p-nitrophenetyl derivatives (7). The protective groups on the side chain diols and N2 of these compounds were selectively cleaved to furnish products 6, 8-10, among which 9 is naturally occurring 3-methyl-L-biopterin and 8 is N',N(3)-protected biopterin, a versatile intermediate for various reactions on the side-chain diol. In contrast, the same Mitsunobu reactions of tri-N2:I',2'-0-acetyl-L-biopterin (II) afforded 04-methyl (12) and 04-NPE derivatives (13), both of which yielded 0 4-methyl-L-biopterin (14) and subsequently led to 4-amino-L-biopterin (18).

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33

Mohareb, Rafat, and Hanaa Hana. "Synthesis of progesterone heterocyclic derivatives of potential antimicrobial activity." Acta Pharmaceutica 58, no. 1 (March 1, 2008): 29–42. http://dx.doi.org/10.2478/v10007-007-0043-3.

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Synthesis of progesterone heterocyclic derivatives of potential antimicrobial activityThe aim of this work was to synthesize steroidal heterocycles and to elucidate the potential role of these compounds as antimicrobial agents. The synthesis of steroidal heterocycles containing the pyrazole, isoxazole, thiazole, pyrane, pyridine, pyridazine, or benzopyrane ring attached to the pregnene nucleus is reported. Progesterone (1) reacts with dimethyl formamide dimethyl acetal to form enamine2. Heterocyclization of2with hydrazines, hydroxylamine, glycine, ethyl acetoacetate or cyanomethylene afforded novel steroidal heterocyclic derivatives. Thein vitroantimicrobial evaluation showed that all synthesized compounds show activity against the used strains of Gram positive bacteria and fungi.

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34

FURUKAWA, Isao, Seiji EBARA, and Shizunobu HASHIMOTO. "Reaction of 1-aryl-2-hydroxy-1-alkanone dimethyl acetal with dihalotriphenylphosphorane." NIPPON KAGAKU KAISHI, no. 9 (1990): 949–54. http://dx.doi.org/10.1246/nikkashi.1990.949.

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35

Ślepokura, Katarzyna, and Irmina Mitaszewska. "Acidic and anionic forms of 1,3-cyclic dihydroxyacetone phosphate (cDHAP) dimethyl acetal." Acta Crystallographica Section C Crystal Structure Communications 67, no. 5 (April 13, 2011): o161—o165. http://dx.doi.org/10.1107/s0108270111011723.

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36

Grubb, Mary F., and Patrick S. Callery. "Derivatization of n-methyl and cyclic amino acids with dimethylformamide dimethyl acetal." Journal of Chromatography A 469 (January 1989): 191–96. http://dx.doi.org/10.1016/s0021-9673(01)96454-4.

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37

Azzena, Ugo, Maria Vittoria Idini, and Luciano Pilo. "Synthesis of Antibiotic Stilbenes by Reductive Metalation of 3,4,5-Trimethoxybenzaldehyde Dimethyl Acetal." Synthetic Communications 33, no. 8 (January 5, 2003): 1309–17. http://dx.doi.org/10.1081/scc-120018690.

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38

Shintani, Akinori, Masanori Inagaki, Hiroshi Kohda, and Yoshio Takeda. "Vincoside Lactam and Secologanin Dimethyl Acetal from the Leaves of Davidia involucrata." Chemistry of Natural Compounds 53, no. 3 (May 2017): 598–99. http://dx.doi.org/10.1007/s10600-017-2063-7.

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39

Xu, Jiao, Li Hong Zhang, Xiu Bo Liu, Wei Ma, Ling Ma, Yan Ma, Jian Nan Yang, and Dao Lin Wang. "Catalyst-Free, One-Pot, Three-Component Synthesis of Pyrimido[4,5-b] Quinoline-4-Amines under Microwave Irradiation." Journal of Chemical Research 42, no. 10 (October 2018): 525–28. http://dx.doi.org/10.3184/174751918x15366615479040.

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An efficient and facile one-pot, three-component protocol for the synthesis of pyrimido[4,5-b]quinoline-4-amines from the condensation of 2-aminoquinoline-3-carbonitrile, N,N-dimethylformamide dimethyl acetal and primary amines under microwave irradiation is reported. This efficient, straightforward procedure led to the desired products in high yields without the need for a catalyst or for a tandem addition–elimination–cyclisation reaction.

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40

Kresge, A. J., M. Leibovitch, and K. R. Kopecky. "Acid-catalyzed hydrolysis of tetramethoxyethene in aqueous solution. Initial state stabilization by the methoxy groups." Canadian Journal of Chemistry 68, no. 10 (October 1, 1990): 1786–90. http://dx.doi.org/10.1139/v90-278.

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The acid-catalyzed hydrolysis of tetramethoxyethene to methyl dimethoxyacetate in aqueous solution at 25 °C was found to occur with the hydronium-ion catalytic coefficient [Formula: see text], to give the solvent isotope effect [Formula: see text], and to provide a Brønsted relation based upon six carboxylic acids with the exponent α = 0.42. These data indicate that the reaction proceeds via rate-determining proton transfer from the catalyzing acid to an olefinic carbon atom of the substrate. They also show tetramethoxyethene to be 1.0 × 106 times less reactive than 1,1-dimethoxyethene (ketene dimethyl acetal), a rate retardation 600 times greater than that expected from initial state stabilization by the two additional methoxy groups in tetramethoxyethene; possible causes of this disparity are discussed. Keywords: tetramethoxyethene, carbon–carbon double bond reactivity, ketene acetal, vinyl ether hydrolysis.

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41

Rosa, Rui, António Manuel Marques, María Leonor Nunes, Narcisa Bandarra, and Carlos Sousa Reis. "Spatial-temporal changes in dimethyl acetal (octadecanal) levels of Octopus vulgaris (Mollusca, Cephalopoda): relation to feeding ecology." Scientia Marina 68, no. 2 (June 30, 2004): 227–36. http://dx.doi.org/10.3989/scimar.2004.68n2227.

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42

Hanna, Naeem B., Milena Masojídková, and Alois Pískala. "Synthesis and Biological Activity of N4-Methyl-5-azacytidines." Collection of Czechoslovak Chemical Communications 63, no. 5 (1998): 713–22. http://dx.doi.org/10.1135/cccc19980713.

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Protected N4-methyl and N4,N4-dimethyl derivatives of 5-azacytidine 3 and 4 were prepared by selective aminolysis of benzoylated 4-methoxy-1-(β-D-ribofuranosyl)-1,3,5-triazin-2(1H)-one 5, by glycosylation of silylated N4-methyl- or N4,N4-dimethyl-5-azacytosines 7 and 8 with 2,3,5-tri-O-benzoyl-α,β-D-ribofuranosyl chloride (11) or by several modifications of the isocyanate method. By the isocyanate approach, also the α-D anomer of protected N4-methyl-5-azacytidine 17 was obtained as a minor product. The protected dimethyl derivative 4 was also obtained by the reaction of isobiuret 22 with dimethylformamide dimethyl acetal. The free nucleosides 1 and 2 were obtained either by aminolysis of the free methoxy nucleoside 23 with methylamine or dimethylamine, respectively, or by methanolysis or ammonolysis of the corresponding benzoyl derivatives 3 and 4. The free α-D anomer 24 was obtained by methanolysis of its tribenzoate 17. Nucleosides 1 and 2 exhibited a lower antibacterial, antitumor and antiviral activity than the unsubstituted 5-azacytidine.

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43

Fleischhauer, Jörg, Sven Gabriel, Dieter Ender, Anja Nühring, and Axel Wollmer. "CD-Spectroscopic Investigations for the Determination of the Absolute Configuration of α-Alkylated 1,4-CycIohexanedione Derivatives." Zeitschrift für Naturforschung B 55, no. 11 (November 1, 2000): 1011–14. http://dx.doi.org/10.1515/znb-2000-1104.

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The absolute configuration of the conformationally flexible six membered ring system 2-methyl- and 2,6-dimethyl-l,4-cyclohexanedione monoethylene acetal was determined by comparison of measured and calculated CD spectra. The rotational strengths were calculated by means of the CNDO/S-method assuming R at the stereogenic center. The results were compared with the predictions made by the octant rule. The enantiomerically pure material was synthesized via the corresponding SAMP- and RAMP-hydrazones.

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44

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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45

Negriolli, Jérôme, Daniel Maume, David Deniaud, and François André. "Corticosteroid derivatization: Unexpected results obtained using N,N-dimethylformamide dimethyl acetal on dexamethasone." Tetrahedron Letters 37, no. 30 (July 1996): 5365–66. http://dx.doi.org/10.1016/0040-4039(96)01145-8.

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46

Li, Weidong, Xiaochun Zhang, Auke Meetsma, and Bart Hessen. "Palladium-Catalyzed Copolymerization of Ethene with Acrolein Dimethyl Acetal: Catalyst Action and Deactivation." Journal of the American Chemical Society 126, no. 39 (October 2004): 12246–47. http://dx.doi.org/10.1021/ja045948y.

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47

Abu-Shanab, Fathi A., Fawzy M. Aly, and Basil J. Wakefield. "Synthesis of Substituted Nicotinamides from Enamines Derived from N,N-Dimethylformamide Dimethyl Acetal." Synthesis 1995, no. 08 (August 1995): 923–25. http://dx.doi.org/10.1055/s-1995-4039.

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48

Kumar, Akshay, and Swapandeep Singh Chimni. "Organocatalytic Asymmetric Direct Aldol Reaction of Pyruvic Aldehyde Dimethyl Acetal with Isatin Derivatives." European Journal of Organic Chemistry 2013, no. 22 (June 17, 2013): 4780–86. http://dx.doi.org/10.1002/ejoc.201300411.

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49

Mataka, Shuntaro, Yoshiro Shimojyo, Iwao Hashimoto, and Masashi Tashiro. "Benzodiimidazoles by reaction of benzenetetramines and benzenehexamines with dimethylformamide and its dimethyl acetal." Liebigs Annalen 1995, no. 10 (October 1995): 1823–25. http://dx.doi.org/10.1002/jlac.1995199510255.

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50

Theil, Fritz, and Hans Schick. "Investigation of the dimethyl acetal formation during the Ozonization of Alkenes in methanol." Journal f�r Praktische Chemie 329, no. 4 (1987): 699–704. http://dx.doi.org/10.1002/prac.19873290419.

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