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Васильцов, А. М.; Shmidt, E. Yu.; Михалева, А. И.; Афонин, А. В.; Zaitsev, Alexey B.

doi:10.1023/a:1014501108513

Cited by 9 publications

(2 citation statements)

References 2 publications

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“…Due to their wide utility as biologically active agents and key intermediates in organic synthesis, pyrrole derivatives have attracted significant attention from organic chemists, and a variety of efficient methods have been developed for their synthesis. Examples include Hantzsch, [13][14][15][16][17][18] Trofimov, [19][20][21][22] Mannich [23][24][25][26] and Clauson-Kaas reactions, [27][28][29][30] Friedel-Crafts, [31][32][33][34] and [3+2] cycloadditions. [35][36][37][38][39] In recent years, metal-free catalysis of various organic transformations has gained more and more attention.…”

Section: Introductionmentioning

confidence: 99%

Acid-induced intermolecular [3+2] cycloaddition/oxidation to synthesize polysubstituted benzo[f]isoindole-4,9-diones

Lin

et al. 2019

Journal of Chemical Research

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A novel one-pot 1,3-dipolar cycloaddition/oxidation reaction of 1,4-quinones, aromatic aldehydes, and N-substituted amino esters to construct polysubstituted benzo[ f]isoindole-4,9-diones induced by benzoic acid is reported. Based on optimized reaction conditions, various polysubstituted benzo[ f]isoindole-4,9-diones derivatives are obtained in moderate yields. This straightforward methodology employs mild reaction conditions, a green oxidant, and readily available starting materials. Notably, a wide range of substrates is tolerated.

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Section: Introductionmentioning

confidence: 99%

Acid-induced intermolecular [3+2] cycloaddition/oxidation to synthesize polysubstituted benzo[f]isoindole-4,9-diones

Lin

et al. 2019

Journal of Chemical Research

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“…This makes available a large number of previously unknown pyrroles and N-vinylpyrrole compounds of various structures [12][13][14], including steroids. The ability to use the method to synthesize pyrrole-containing steroids was studied using progesterone oximes, ' 5 -pregnen-3E-ol-20-one and ' 5 -cholesten-3-one as examples [15][16][17].Herein we describe the first example of a Trofimov reaction of pentacyclic triterpenoids. Oximes of 3-keto derivatives of lupane-type pentacyclic triterpenoids are convenient subjects for studying the Trofimov reaction.…”

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confidence: 99%

Trofimov synthesis of betulin derivatives with 2,3-annelated pyrrole

et al. 2011

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Lupane-type triterpenoid derivatives containing a 2,3-annelated 1H-pyrrole or an N-vinylpyrrole moiety were synthesized by reaction of 28-OTr-lup-20(29)-en-3-one oxime and acetylene in KOH/DMSO superbase medium at atmospheric pressure.Annelation of N-containing heterocycles with the triterpene skeleton is a promising and developing method for modifying pentacyclic triterpenoids of the lupane and oleanane types, natural compounds with broad spectra of biological activity [1].Annelated structures are usually synthesized using classical methods. Pyrazine and quinoxaline derivatives of lupaneand oleanane-type triterpenoids were prepared at various times by condensation of triterpene D-diketones, D-gem-dibromo-or D-bromoketones with ethylene-or o-phenylenediamines [2][3][4][5]. Pyrazolo-triterpenoid structures were synthesized by condensation of E-diketones with R-hydrazines (R = H, Me) [6-8]. Reaction of lupane 3-oxo-2-ketenedithioacetal with hydrazine or guanidine produced substituted pyrazoles and pyrimidines [9]. A large series of indole derivatives of lupane-type triterpenoids was recently prepared by Fisher condensation of betulonic and dihydrobetulonic acids with arylhydrazines. High anticancer activity against various cell lines that was not known earlier was found for 2,3-indole-containing lupane-C-28-carboxylic acids. The most active of them were indoles with an unsubstituted N atom. The only compound containing a pyrrole ring annelated to a triterpene skeleton was the N-benzyl-4-phenylpyrrole derivative obtained from dihydrobetulonic acid condensed with benzylamine that underwent subsequent Michael reaction to form an imine with PhCH=CHNO 2 [10].The pyrrole ring is a key element of fundamentally vital natural compounds such as chlorophyll, hemoglobin, vitamin B12, factor 430, biologically active compounds, and many drugs [11]. The development of effective synthetic methods for hybrid pentacyclic triterpenoids with a pyrrole ring opens the door to biologically active compounds with new and improved pharmacological properties.An effective method for forming a pyrrole ring is Trofimov nucleophilic addition of ketoximes to acetylene in superbase media. This makes available a large number of previously unknown pyrroles and N-vinylpyrrole compounds of various structures [12][13][14], including steroids. The ability to use the method to synthesize pyrrole-containing steroids was studied using progesterone oximes, ' 5 -pregnen-3E-ol-20-one and ' 5 -cholesten-3-one as examples [15][16][17].Herein we describe the first example of a Trofimov reaction of pentacyclic triterpenoids. Oximes of 3-keto derivatives of lupane-type pentacyclic triterpenoids are convenient subjects for studying the Trofimov reaction. They are available and are formed as a single isomer. The presence in one of the D-positions of a bulky gem-dimethyl substituent prevents the formation of regioisomers of the pyrrole rings. Betulin (1) was selectively protected at the primary hydroxyl by tritylchloride (TrCl). The resulting compound 2 was oxidized ...

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Trofimov Reaction

2010

Comprehensive Organic Name Reactions and Reagents

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The synthesis of 2‐substituted, 2,3‐, or 2,5‐disubstituted pyrroles or N ‐vinylpyrroles from ketoximes and acetylene in a superbasic solution (i.e., MOH/DMSO, M = Li, Na, K) is generally known as the Trofimov reaction. This reaction has been carried out using an even stronger base (e.g., alkali metal alkoxide) along with alkali hydroxide in N ‐methylpyrrolidone to give better yields. In addition, a straightforward one‐pot transformation of ketone into 2,3‐disubstituted pyrrole or N‐ vinylpyrroles by the consecutive reaction of a ketone with hydroxylamine and acetylene in DMSO/KOH has been developed. This reaction is very useful in the preparation of pyrrole derivatives.

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Cited by 9 publications

References 2 publications

Acid-induced intermolecular [3+2] cycloaddition/oxidation to synthesize polysubstituted benzo[f]isoindole-4,9-diones

Acid-induced intermolecular [3+2] cycloaddition/oxidation to synthesize polysubstituted benzo[f]isoindole-4,9-diones

Trofimov synthesis of betulin derivatives with 2,3-annelated pyrrole

Trofimov Reaction

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