Synthesis and Antimicrobial Activity of Some Annelated Quinazoline Derivatives

One-pot synthesis of 1,3,5-triazine-2,4-dithione derivatives via three-component reactions

A catalyst-free one-pot synthetic methodology was developed for the preparation of 1,3,5-triazine-2,4-dithione derivatives through three-component reactions of arylaldehydes, thiourea, and orthoformates. The procedure tolerated a diverse range of arylaldehydes and orthoformates and provided a rapid entry to a variety of 4-aryl-6-(alkylthio)-3,4-dihydro-1,3,5-triazine-2(1H)-thiones (29 examples). The synthetic strategy relies on the dual role of thiourea in the cyclization with the aldehydes and the alkylation via an intermediate imidate formation. The structures of 1,3,5-triazine-2,4-dithione derivatives were characterized by spectroscopic techniques as well as by single crystal X-ray diffraction.

A novel method for heterocyclic amide-thioamide transformations

In this paper, we introduce a novel and convenient method for the transformation of heterocyclic amides into heteocyclic thioamides. A two-step approach was applied for this transformation: Firstly, we applied a chlorination of the heterocyclic amides to afford the corresponding chloroheterocycles. Secondly, the chloroherocycles and N-cyclohexyl dithiocarbamate cyclohexylammonium salt were heated in chloroform for 12 h at 61 °C to afford heteocyclic thioamides in excellent yields.

Synthesis and antimicrobial evaluation of some 6-aryl-5-cyano-2-thiouracil derivatives

A series of 6-aryl-5-cyano-2-thiouracil derivatives (1a-d) was synthesized by the reaction of ethyl cyanoacetate with thiourea and aldehydes. These products were used as intermediate compounds for the synthesis of a number of thiouracil derivatives (2a-d to 10a-d). All compounds were screened for antibacterial and antifungal activities. Some of the prepared compounds, 6-(4-fluorophenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide (2a), 4-oxo-2-thioxo-6-(3,4,5-trimethoxyphenyl)-1,2,3,4-tetrahydropyrimidine-5-carboxamide (2d), 6-(4-fluorophenyl)-4-hydrazino-2-thioxo-1,2-dihydropyrimidine-5-cabonitrile (7a) and 4-hydrazino-2-thioxo-6-(3,4,5-trimethoxyphenyl)-1,2-dihydropyrimidine-5-carbonitrile (7d) revealed promising antimicrobial activity.