Nadezhda I. Protsuk

Base‐Catalyzed Stereoselective Vinylation of Ketones with Arylacetylenes: A New C(sp3)C(sp2) Bond‐Forming Reaction

Alkylaryl- and alkylheteroarylketones, including those with condensed aromatic moieties, are readily vinylated with arylacetylenes (KOH/DMSO, 100 degrees C, 1 h) to give regio- and stereoselectively the (E)-beta-gamma-ethylenic ketones ((E)-3-buten-1-ones) in 61-84% yields and with approximately 100% stereoselectivity. This vinylation represents a new C(sp(3))-C(sp(2)) bond-forming reaction of high synthetic potential.

A General Synthetic Strategy for the Design of New BODIPY Fluorophores Based on Pyrroles with Polycondensed Aromatic and Metallocene Substituents

BODIPYrrole: A general strategy for the design of novel BODIPY fluorophores based on pyrroles with polycondensed aromatic and metallocene substituents has been developed. The strategy involves the acylation of the condensed substituent and treatment of the acylated derivative (as oxime) with acetylene in MOH/DMSO (M = alkali metal) to give pyrroles that were then used for assembly of the BODIPY fluorophores (see scheme).

Selective synthesis of 1-vinylpyrroles directly from ketones and acetylene: Modification of trofimov reaction

Consecutive treatment of ketones with a system NH2OH·HCl-NaHCO3-DMSO and acetylene excess in the presence of KOH (100–120°C, initial acetylene pressure 12–15 at) led to a selective formation of 2-and 2,3-substituted 1-vinylpyrroles in 51–79% yields. Ketones of aliphatic, cycloaliphatic, aromatic, heteroaromatic, and tetrahydronaphthalene series were involved into the reaction.

Improved synthesis of tertiary propargyl alcohols by the Favorskii reaction of alkyl aryl (hetaryl) ketones with acetylene

Alkyl aryl (hetaryl) ketones react with acetylene under atmospheric pressure in the superbasic system KOH-EtOH-H2O-DMSO at 10–15°C (2 h) to give the corresponding tertiary propargyl alcohols in up to 91% yield. The procedure requires no large excess of KOH and low-boiling inflammable solvents, produces few wastes, and is safe and convenient on the laboratory scale; there are no limitations for its large-scale application.

Electrophilic addition of alcohols to 1-vinyl-2-phenylazopyrroles and unexpected formation of 2-methylquinoline

Abstract1-Vinyl-2-phenylazopyrroles react with alcohols in the presence of acids or PdCl2 to give 1-(1-alkoxyethyl)-2-phenylazopyrroles in up to 49% yield. In the presence of trifluoroacetic acid 2-methylquinoline unexpectedly formed (yield up to 26%) involving into the reaction the phenylazo and 1-vinyl groups.

NMR study of C- and N-trimethylsilylazole derivatives

C‐ and N‐trimethylsilylazole derivatives were studied by 1H, 13C and 29Si NMR spectroscopy. Degenerated prototropic tautomerism of 4‐trimethylsilylpyrazole in methanol and the silylotropy of 1‐trimethylsilyl‐4‐methylpyrazole in a neat liquid were investigated for the first time. 3‐ and 5‐tautomers of 3(5)‐methylpyrazole in a ratio of 54:46 were found in methanol by use 13C NMR spectroscopy (Tc=230 K, ΔGc≠=10 kcal mol‐1).

Tautomerism of 3-nitro-1,2,4-triazole-5-one radical anions

The non‐degenerate tautomers of 3‐nitro‐1,2,4‐triazole‐5‐one (NTO) radical anions were investigated for the first time by an ESR method during electrochemical reduction of NTO in an aprotic medium. Copyright

Dithiobiuretes in reactions with electrophilic acetylenes. New derivatives of 1,3,5-dithiazines,-thiadiazines and-triazines as the products of competing reactions of nucleophilic cycloaddition

The nucleophilic addition of 2,4-dithiobiurete, 1- and 1,4-substituted 2,4-dithiobiuretes (2 a-e) with benzoylacetylene (1) has been studied. 2-(Benzoylmethyl)-4-(R1-imino)-6-(R2-imino)dihydro-4H-1,3,5-dithiazinium perchlorates (3 a-e) are obtained in glacial acetic acid (AcOH) in the presence of equimolar quantities of HClO4. The reaction of benzoylacetylene with 1,5-diphenyl-2,4-dithiobiurete in either of MeOH, C6H6, or MeCN solvents proceeds non-selectively to give a mixture of products such as 2-(benzoylmethyl)-4,6-di(phenylimino)dihydro-4H-1,3,5-dithiazine (5), 2-(benzoylmethyl)-4-(β-benzoylvinyl)thio-3-phenyl-6-(phenylimino)-3,6-dihydro-2H-1,3,5-thiadiazine (8), 2-(benzoylmethyl)-1,3-diphenylhexahydro-1,3,5-triazine-4,6-dithione (7) and N-(β-benzoylvinyl)-N-phenylthioureas (6).

A One-Pot Synthesis of 2-Aminopyrimidines from Ketones, Arylacetylenes, and Guanidine

The three-component reaction of ketones, arylacetylenes, and guanidine catalyzed by the KOBut/DMSO system leads to 2-aminopyrimidines in up to 80% yield. Depending on structure of the starting ketones, the aromatization of intermediate dihydropyrimidines occurs either with loss of hydrogen molecules or methylbenzenes. The latter process takes place in the ketones, in which one of the substituents is not a methyl group. The reaction conditions are tolerable for dialkyl-, aryl(hetaryl) alkyl-, and cycloalkyl ketones.

IMPROVED METHOD FOR THE SYNTHESIS OF 1-VINYLINDOLE

A highly efficient method has been developed for the synthesis of 1-vinylindole based on the vinylation of indole by acetylene at atmospheric pressure using the superbase KOH–DMSO catalytic system. The method allows the preparation of the 1-vinylindole in 94% yield with a purity of 99% (after a single distillation of the crude product).