Syntheses based on 2-ethoxycarbonylmethyl-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-5(5H)-one

2-Ethoxycarbonylmethyl-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-5(5H)-one containing the active methylene group reacts easily with carbon disulfide and phenyl isothiocyanate in the presence of sodium hydride. Further alkylation of the reaction product by alkyl halides results in the formation of the corresponding 1,3,4-thiadiazolo[3,2-a]pyrimidine derivatives containing a ketene dithioacetal fragment. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2371–2373, November, 1998.     

Polyfunctional nitriles in the synthesis of derivatives of 1,3,4-thiadiazolo-[3,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidines

A one-pot method has been developed for the synthesis of 2-R-7-methyl-5-oxo-5H-1,3,4-thia-diazolo[3,2-a]pyrimidine by condensation of β-alkylthio(alkoxy)propionitrile, thiosemicarbazide, and ethyl acetoacetate in PPA, and also (7-methyl-5-oxo-5H-1,3,4-thidiazolo[3,2-a]pyrimidin-2-yl)-acetamide from cyanoacetamide, thiosemicarbazide, and ethyl acetoacetate. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, 1096–1100, July, 2008.     

Synthesis and transformations of hydrazinecarbo-dithioates containing the 7-methyl-,5-oxo-5h-1,3,4 thiadiazolo[3,2-a]pyrimidin-2-yl fragment

The reaction of 2-hydrazino-7-methyl-5-ozo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine with carbon disulfide leads to the formation of hydrazinecarbodithioates and their cyclization products.V. I. Nikitina Institute of Chemistry, Academy of Sciences of the Republic of Tadzikistan, Dushanbe 734063. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 560–562, April, 1994. Original article submitted December 13, 1993.