Synthesis of monothiooxamides

A convenient method for the synthesis of monothiooxamides by the reaction of chloroacetamides with a solution of elemental sulfur in amines was developed.     

Synthesis of monothiooxamides of the thiazole series

A convenient method for the synthesis of previously inaccessible monothiooxamides of the thiazole series was developed. The method is based on the reaction of pyridinium salts obtained from 2-(chloroacetylamino)thiazole and pyridine with a solution of elemental sulfur and amines prepared beforehand.     

Synthesis of heterocyclic compounds based on oxamic acid monothiooxamides and thiohydrazides

The review integrates and systematizes the key chemical transformations of monothiooxamides and thiohydrazides of oxamic acids and their derivatives, which give rise to various five-, six-, and seven-membered heterocyclic compounds with several heteroatoms.

     

Reactions of monothiooxamides with N-nucleophiles. Synthesis of 4,5-dihydroimidazole-2-carboxanilides

A convenient procedure was developed for the preparation of 4,5-dihydroimidazole-2-carboxanilides by the reaction of monothiooxamides with ethylenediamine. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 753–757, April, 1999.     

Synthesis of 2-thioxo-1,3-thiazolidin-4-one derivatives

A series of new 2-thioxo-1,3-thiazolidin-4-one derivatives containing arylidene, arylazo, and aminomethylene fragments in position 5 of the rhodanine cycle was synthesized. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1564–1569, August, 2007.     

Reactions of 17-chloro-16-formylandrosta-5,16-diene with thiohydrazides of oxamic acids

Reactions of thiohydrazides of oxamic acids with 17-chloro-16-formylandrosta-5,16-diene give the corresponding thiohydrazones at the formyl group. Their subsequent reactions with alkali (het)arenethiolates yield 17-het(aryl)thio derivatives, being accompanied by cyclization of the thiooxalylhydrazone fragment into a 1,3,4-thiadiazole ring.     

Interaction of 16-hydroxymethylidene derivatives of androstane and estrone with thiohydrazides of oxamic acids

Reaction of thiohydrazides of oxamic acids with 16-hydroxymethylidene derivatives of androstane and estrone involves the hydroxymethylidene group and leads to thiohydrazones, which undergo heterocyclization to give 16-(1,3,4-thiadiazol-2-yl)-substituted steroids.     

Synthesis and reactivity of monothiooxamides of the aminonitroarene series

Russian Chemical Bulletin - Monothiooxamides containing aminonitrobenzene and aminonitropyridine fragments have been synthesized. A possibility to synthesize thioesters and fused imidazole and...     

Synthesis of thieno[2,3-d]pyrimidine and quinazoline derivatives from monothiooxamides

A method for syntheses of previously unknown derivatives of thieno[2,3-d]pyrimidines and quinazolines from monothiooxamides was proposed.     

Synthesis and reactivity of furazanyl- and furoxanyldiazonium salts

Diazotization of aminofurazans (1) and 4-aminofuroxans (2) with nitrosylsulfuric acid in a mixture of conc. H₂SO₄ and H₃PO₄ has been studied and offered as a general method for preparing furazanyl- (3) and furoxanyldiazonium (4) salts. It has been shown that reactions with the retention of the N-N-group (azo coupling, formation of triazenes and azides) are typical of salts3 and4, while elimination of the N₂ molecule (Sandmeyer reaction, hydrolysis, reduction) is not typical.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1949–1953, November, 1993.     

Synthesis of 4,5-Dihydro-1,3,4-thiadiazole-2-carboxamide and 2-Carbamoyl-4,5-dihydro-1,3,4-thiadiazole 1-Oxide Derivatives Based on Hydrazones of Oxamic Acid Thiohydrazides

We have developed a method for obtaining derivatives of 4,5-dihydro-1,3,4-thiadiazole-2-carboxamide by acylation of hydrazones of oxamic acid thiohydrazides. Oxidation of the dihydrothiadiazole ring of the indicated products by hydrogen peroxide leads to formation of 2-carbamoyl-4,5-dihydro-1,3,4-thiadiazole 1-oxides.     

Separation of perfluoroalkylsulfinic acids and perfluoroalkylsulfonic acids by ion-exclusion chromatography

Ion-exclusion chromatography has been successfully applied to the separation of a number of perfluoroalkylsulfinic acids and perfluoroalkylsulfonic acids. The separation of various perfluoroalkylsulfinic and perfluoroalkylsulfonic acids, with different alkyl groups, was investigated on a polymethacrylate-based, weakly acidic, cation-exchange resin (TSK gel OApak-A) in the H⁺-form and using conductimetric detection. When water was used as the eluent, these perfluoroalkylsulfinic and perfluoroalkylsulfonic acids could not be resolved. When an aqueous solution of benzoic acid and o-phthalic acid was used, the separation of each of these acids occurred. In order to improve their separation, the effect of the addition of methanol and 2,2,2-trifluoroethanol, as organic modifiers, was also investigated.     

Enantiospecific synthesis of 3-aza-6,8-dioxa-bicyclo[3.2.1]octane carboxylic acids from erythrose

New methodology for the synthesis of enantiopure 3-aza-6,8-dioxa-bicyclo[3.2.1]octane-carboxylic acids belonging to 7-endo-BTAa sub-class of γ/δ amino acids is described. The novelty is the use of 2,3-O-isopropylidene-erythrose instead of meso-tartaric acid derivative, thus allowing us to perform an enantiospecific synthesis. Reductive amination of erythrolactol with aminoacetaldehyde diethylacetal or benzylamine, and subsequent acid cyclisation gave directly the amino alcohol scaffold. Protection of nitrogen as urethane and final alcohol oxidation afforded the Fmoc-, Boc-, and Cbz-amino acids. The new synthetic route was applied to multigram scale, thus resulting in a marked improvement of the synthesis of enantiopure 7-endo-BTG and 7-endo-BTK amino acids.     

Nucleophilic Vinyl Substitution in the Synthesis of Heterocycles. (Review)

Published data on the synthesis of various heterocyclic compounds by the reaction of nucleophiles with electrophilic olefins containing a nucleophilic group are reviewed and analyzed.     

Synthesis, structure and reactivity of organogold compounds of relevance to homogeneous gold catalysis

Organogold(I) phosphane complexes were prepared, their structure was investigated and their reactivity in reactions with Michael acceptors, sources of electrophilic halogens and protons were investigated.     

Synthesis and characterization of new pyrido-thieno-pyrimidine derivatives incorporating pyrazole moiety

2-Hydrazinyl-pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one was reacted with commercially available active methylene compounds (e.g., acetylacetone, ethyl acetoacetate, and diethyl malonate) and ethoxymethylenemalononitrile to afford the respective pyrazole derivatives. Moreover, the prepared pyrazolinone was utilized for synthesis of some new arylidene-, arylazo-pyrazolinone, and azolo-triazine derivatives. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, ¹H NMR, and mass spectral data.     

Synthesis and characterization of new 4,5-dihydropyrazol-1-yl derivatives

In this study, first, a series of chalcone compounds S1–S6 were synthesized from various acetophenone derivatives (acetophenone, p-methyl acetophenone, and p-methoxy acetophenone) and aromatic aldehyde derivatives (benzaldehyde, p-methyl benzaldehyde, and p-methoxy benzaldehyde) by the Claisen–Schmidt condensation reaction. These S1–S6 compounds were then used in the preparation of 4,5-dihydropyrazol-1-yl derivatives S7–S15. Finally, four new compounds S16–S19 were synthesized from compound (S7, S8, S9, and S12) and 2,4-dinitrophenylhydrazine. Therefore, three known and ten new heterocyclic compounds were synthesized and completely characterized using ¹H NMR, ¹³C NMR, IR, and elemental analysis.