A. S. Nakhmanovich

Thiophene-2-carbaldehyde and benzaldehyde thiosemicarbazones in reactions with propargyl bromide and 1,3-dibromopropyne

The reaction of thiophene-2-carbaldehyde and benzaldehyde thiosemicarbazones with propargylbromide in methanol provided S-(2-propyne)thiosemicarbazones hydrobromides of thiophene-2-carbaldehyde and benzaldehyde. Reaction products obtained from thiosemicarbazones and 1,3-dibromopropyne in methanol at heating were 2-thenilydene(benzylidene)azino-4-bromomethylidene-4,5-dihydrothiazol-3-ium bromides.

Vicarious C-amination of 1-methyl-4-nitroimidazole

A one electron transfer process during the vicarious nucleophilic substitution C-amination of 1-methyl-4-nitroimidazole is detected by EPR-monitoring.

Structure of N,N-dimethylhydrazone alkylation products

Abstract Alkylation of 1,1-dimethylhydrazone-4- and -3-pyridinaldehydes has been shown, by means of multinucleus 1D- and 2D NMR spectroscopy and quantum chemistry (ab initio), to proceed exclusively by the pyridine nitrogen atom to form the corresponding pyridinium halides. At the same time, 1,1-dimethylhydrazone benzaldehyde is alkylated to the amine nitrogen with the formation of hydrazonium salts.

Reaction of 2-(2-Cyanoethyl)-1,1-dimethylhydrazine with Prop-2-ynyl Bromide, 1,3-Dibromopropyne, and Allyl Bromide

The reactions of 2-(2-cyanoethyl)-1,1-dimethylhydrazine with prop-2-ynyl bromide, 1,3-dibromopropyne, and allyl bromide involve alkylation by a tertiary nitrogen atom to form 2-(2-cyanoethyl)-1,1-dimethyl-1-(prop-2-ynyl)-, 1-(3-bromoprop-1-ynyl)-2-(2-cyanoethyl)-1,1-dimethyl-, and 1-allyl-2-(2-cyanoethyl)-1,1-dimethylhydrazinium bromides.

Synthesis of substituted 2-amino-1,3-thiazine-6-thiones

The reaction of thiourea with l-acyl-2-bromoacetylenes in AcOH in the presence of BF3·Et2O affords 2-amino-4-phenyl(2-thienyl)-1,3-thiazine-6-thiones in high yields.

Synthesis of 1-[1-bromo-2-benzoyl(2-thenoyl)vinyl]-1,1-dimethylhydrazinium bromides from 1-bromo-2-benzoyl(2-thenoyl)acetylenes and 1,1-dimethylhydrazine

Abstract1-[1-Bromo-2-benzoyl(2-thenoyl)vinyl]-1,1-dimethylhydrazinium bromides were synthesized by the reactions of 1-aroyl-2-bromoacetylenes withN,N-dimethylhydrazine in acetonitrile at 20°C. The structure of 1-(2-benzoyl-1-bromovinyl)-1,1-dimethylhydrazinium bromide was established by X-ray diffraction analysis.

Synthesis ofN-substituted 4-benzoyl-2-iminothiazolium bromides

Substituted thioureas react with 1-bromo-2-benzoylacetylene in various solvents at 20°C to give the correspondingN-substituted 4-benzoyl-2-(R-imino)-3-R′-thiazolium bromides.

Reaction of acylacetylenes and methyl propiolate with N,N′-bis(dithiocarboxy)piperazine

The reaction of N,N′-bis(dithiocarboxy)piperazine with acetylenic ketones and methyl propiolate gave N,N′-bis(acylvinyldithiocarbo)- and N,N′ -bis(methoxy-carbonylvinyldithiocarbo)piperazines. Heating the compounds obtained with perchloric acid leads to intramolecular cyclization with the formation of N,N′ -bis[2-acyl(methoxycarbonyl)methyl-1,3-dithietanium]piperazine perchlorates.

Quinoxaline-2,3-dithiol in reactions with propargyl bromide and 1,3-dibromopropyne

Propargyl bromide with quinoxaline-2,3-dithiol in DMSO in the presence of K2CO3 affords 2,3-bis-(2-propynylsulfanyl)quinoxaline in good yield whereas in absolute methanol in the presence of sodium methoxide at 20°C a 1:2 mixture of 2,3-bis(2-propynylsulfanyl)quinoxaline and 3-(2-propynylsulfanyl)-2(1H)-quinoxalinethione is formed. Individual 3-(2-propynylsulfanyl)-2(1H)-quinoxalinethione was obtained by crystallization of this mixture from ether. The reaction of 1,3-dibromopropyne with quinoxaline-2,3-dithiol in ethanol in the presence of NaOH at heating results in 2-bromomethylidene-1,4-(3H)-dithiino[2,3-b]quinoxaline in 77% yield. Performing this reaction in methanol in the presence of sodium methoxide during long heating (16 h) led to 2,3-bis[(3-bromo-2-propynyl)sulfanyl]quinoxaline in 72% yield.

Reaction of thiosemicarbazide with 1,3-dibromopropyne

Thiosemicarbazide reacted with an equimolar amount of 1,3-dibromopropyne in aqueous ethanol (1:1) to give (4-bromomethylidenethiazolidin-2-ylidene)hydrazine hydrobromide. The reaction of thiosemicarbazide with 2 equiv of 1,3-dibromopropyne in ethanol on heating resulted in the formation of 3,6-bis-(bromomethylidene)-3,4,6,7-tetrahydro-2H-thiazolo[2,3-c][1,2,4]triazine hydrobromide. The corresponding free base was obtained when the reaction performed in the presence of triethylamine.