A novel thermal rearrangement of allylic nitro derivatives into allylic alcohols

Addition of nitroethane to 1,2:3,4-di-O-isopropylidene-α-D-galacto-hexodialdo-1,5-pyranose (3) gave a mixture of β-nitro alcohols (4), which was acetylated to afford a mixture of β-nitro acetates (5). Dehydroacetylation of the latter gave cis- and trans-6,7,8-trideoxy-1,2:3,4-di-O-isopropylidene-7-C-nitro-α-D-galacto-oct-6-enose (6 and 7) in a ratio of about 6:1, respectively. Addition of ammonia to the cis-nitroolefin (6) gave rapidly a mixture of two stereoisomeric vic-nitroamines (8), which was acetylated to furnish a mixture of two 6-acetamido-6,7-dideoxy-7-C-nitro derivatives (9). The same products (9) were obtained by the action of ammonia in aqueous tetrahydrofuran upon the preponderant β-nitro acetate, followed by acetylation. Vinylation of the aldehyde 3 gave a mixture of allylic alcohols (10); the preponderant epimer was obtained pure in crystalline form. The various 8-carbon sugar derivatives are of interest as potential intermediates in the synthesis of the carbohydrate moiety in lincomycin.

Download Full-text

Pyrimidine reactions. XVI. Thermal rearrangement of substituted 2- and 4-alkoxypyrimidines

Australian Journal of Chemistry ◽

10.1071/ch9680243 ◽

1968 ◽

Vol 21 (1) ◽

pp. 243 ◽

Cited By ~ 21

Author(s):

DJ Brown ◽

T Lee

Keyword(s):

Electronic Effect ◽

Thermal Rearrangement ◽

Ultraviolet Spectra ◽

Pka Value ◽

Nitro Derivatives ◽

Methyl Derivatives ◽

Spectral Comparison ◽

Derivatives Of ◽

Methyl Bromo

Thermal rearrangement of methyl, bromo, and nitro derivatives of 2- and 4-alkoxy-pyrimidines produced their N-alkyl isomers. These were identified by p.m.r. spectral comparison with synthetic specimens of unambiguous or proven structure. The rates for such isomerizations were measured conveniently by changes in ultraviolet spectra. The C-methyl derivatives rearranged more slowly than the parent alkoxypyrimidines, but the bromo, and especially the nitro, derivatives did so much more quickly. Among the derivatives of each methoxy-pyrimidine, the rate of rearrangement increased as the basic pKa value fell and as the methoxyl protons moved downfield, thus affording a qualitative correlation with properties reflecting the electronic effect of each substituent.

Download Full-text

Active MnO2 As a Mild Oxidizing Reagent for the Controlled Oxidation of Benzylic and Allylic Alcohols

International Journal of Scientific Research ◽

10.15373/22778179/june2013/16 ◽

2012 ◽

Vol 2 (6) ◽

pp. 48-48

Author(s):

Y. M. Nandurkar Y. M. Nandurkar ◽

◽

B. B. Bahule B. B. Bahule

Keyword(s):

Allylic Alcohols

Download Full-text

Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols

10.26434/chemrxiv.8178926 ◽

2019 ◽

Author(s):

Ke-Yin Ye ◽

Terry McCallum ◽

Song Lin

Keyword(s):

Ring Opening ◽

High Reactivity ◽

Hydrogen Atom Transfer ◽

Organic Radicals ◽

Epoxide Ring ◽

Allylic Alcohols ◽

Epoxide Ring Opening ◽

Bond Forming ◽

Co Catalysts ◽

The Rich

Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton-transfer/electron-transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.<br>

Download Full-text

QSAR Analysis of Selected Antimicrobial Structures Belonging to Nitro-derivatives of Heterocyclic Compounds

Letters in Drug Design & Discovery ◽

10.2174/1570180815666181004112947 ◽

2020 ◽

Vol 17 (2) ◽

pp. 214-225 ◽

Cited By ~ 3

Author(s):

Piotr Kawczak ◽

Leszek Bober ◽

Tomasz Bączek

Keyword(s):

Antimicrobial Activity ◽

Heterocyclic Compounds ◽

Molecular Descriptors ◽

Microbiological Activity ◽

Activity Data ◽

Qsar Analysis ◽

Qsar Models ◽

Nitro Derivatives ◽

Semi Empirical ◽

Derivatives Of

Background: Nitro-derivatives of heterocyclic compounds were used as active agents against pathogenic microorganisms. A set of 4- and 5-nitroimidazole derivatives exhibiting antimicrobial activity was analyzed with the use of Quantitative Structure-Activity Relationships (QSAR) method. The study included compounds used both in documented treatment and those described as experimental. Objective: The purpose of this study was to demonstrate the common and differentiating characteristics of the above-mentioned chemical compounds alike physicochemically as well as pharmacologically based on the quantum chemical calculations and microbiological activity data. Methods: During the study PCA and MLR analysis were performed, as the types of proposed chemometric approach. The semi-empirical and ab initio level of in silico molecular modeling was performed for calculations of molecular descriptors. Results: QSAR models were proposed based on chosen descriptors. The relationship between the nitro-derivatives structure and microbiological activity data was able to class and describe the antimicrobial activity with the use of statistically significant molecular descriptors. Conclusion: The applied chemometric approaches revealed the influential features of the tested structures responsible for the antimicrobial activity of studied nitro-derivatives.

Download Full-text

Redox Isomerization of Allylic Alcohols to Carbonyl Compounds Catalyzed by Ruthenium(IV) Complexes Containing N-Heterocyclic Ligands in Ionic Liquids

Current Green Chemistry ◽

10.2174/22133461114016660004 ◽

2013 ◽

Vol 1 (2) ◽

pp. 121-127 ◽

Cited By ~ 7

Author(s):

Francisco J. Suarez ◽

Cristian Vidal ◽

Joaquin Garcia-Alvarez

Keyword(s):

Ionic Liquids ◽

Carbonyl Compounds ◽

Allylic Alcohols ◽

Heterocyclic Ligands ◽

Redox Isomerization

Download Full-text

Regioselectivity of nucleophilic aromatic photosubstitution in the biphenyl series. Photohydrolysis of some dimethoxynitrobiphenyls

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19872482 ◽

1987 ◽

Vol 52 (10) ◽

pp. 2482-2491 ◽

Cited By ~ 1

Author(s):

Ján Urban ◽

Petr Kuzmič ◽

David Šaman ◽

Milan Souček

Keyword(s):

Nitro Group ◽

Steric Hindrance ◽

The Other ◽

Quantum Yields ◽

Hydroxide Anion ◽

Tert Butanol ◽

Nitro Derivatives

Anaerobic photolysis of dimethoxynitrobiphenyls IIIa-VIa in aqueous alkaline tert-butanol gave products of nucleophilic photosubstitution of methoxyl by hydroxide anion, while the dimethoxybiphenyls Ia and IIa were found unreactive. Regioselectivity of the reaction was examined in view of a possible “extended meta activation” by the nitro group. The most reactive substrate IIIa gives both C-3 and C-4 substitution products with an unsubstantial preference for the latter, which opposes the “extended meta selectivity” rule. All of the other compounds obey the rule, and 3,4-dimethoxy-3'-nitrobiphenyl (IVa) even displayed absolute selectivity by yielding C-3 substituted compound as the only product. 2,5-Dimethoxy substituted compounds underwent photosubstitution which much lower quantum yields than their 3,4-substituted counterparts, most probably due to some steric hindrance of conjugation. Similarly, 3-nitro-substituted biphenyls exhibited much lower overall reactivity than 4-nitro derivatives.

Download Full-text

Electrochemical reduction of para-substituted 2-acyl-5-phenylfuranes in dimethylformamide

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19810498 ◽

1981 ◽

Vol 46 (2) ◽

pp. 498-502 ◽

Cited By ~ 4

Author(s):

Jozef Černák ◽

František Tomanovič ◽

Andrej Staško ◽

Anna Fedosyevna Oleinikova ◽

Jaroslav Kováč

Keyword(s):

Electrochemical Reduction ◽

Unpaired Electron ◽

Anion Radical ◽

Electron Wave ◽

Epr Method ◽

Electron Center ◽

Nitrogen Nucleus ◽

Nitro Derivatives ◽

Stable Anion ◽

Derivatives Of

para Substituted chloro, bromo, and nitro derivatives of 2-acyl-5-phenylfurane are reduced polarographically in a one-electron wave to the corresponding anion radicals, which were studied by the EPR method. The reduction of nitro derivatives, studied by the Kalousek switch, is reversible and leads to a stable anion radical with an unpaired electron center on the nitrogen nucleus; the reduction of the halogen derivatives is only partly reversible and leads to unstable ketyl radicals. The bromo derivatives give polarographic maxima typical for concurrent reactions.

Download Full-text