Alkylation and reductive dethionation of 2-thioxo- and 1,2,3,4-tetrahydropyrimidine-5-carboxylic acid derivatives

✍ Scribed by E. L. Khanina; R. M. Zolotoyabko; D. Kh. Mutsenietse; G. Ya. Dubur

• Publisher: Springer US
• Year: 1989
• Tongue: English
• Weight: 507 KB
• Volume: 25
• Category: Article
• ISSN: 0009-3122
• DOI: 10.1007/bf00479609

✦ Synopsis

Methylthio-l,4-dihydropyrimidines were obtained by methylation of 2thioxo-4-phenyl-5-methoxycarbonyl-6-methyl-l,2,3,4-tetrahydropyrimidine or its 1-methyl derivative in a neutral medium. The alkylation of tetrahydropyrimidine-2-thiones in the anionic form leads to S-and S,Nmethylation products. Iodoacetamide alkylates pyrimidine-2-thione with the formation of thiazolidino[3,2-a]pyrimidine derivatives. The reductire dethionation of derivatives of tetrahydropyrimidine-2-thiones and 2-methylthio derivatives of 1,4-and 3,4-dihydropyrimidines was accomplished.

It is known [i, 2] that exclusively S-alkyl derivatives are formed in the alkylation of 2-thioxo-l,2,3,4-tetrahydropyrimidine derivatives in a neutral medium. In the present research we studied the alkylation of methyl 2-thioxo-4-phenyl-6-methyl-l,2,3,4-tetr~hydropyrimidine-5-carboxylate (I) and its l-methyl derivative II in a neutral medium and in the presence of a strong base -sodium hydride.