Cyclocondensation of N-aryl-3-oxobutanethioamides with 5-amino-3-R-4-R1-pyrazoles.

The cyclocondensation products of N-aryl-3-oxobutanethioamides with 5-amino-3-R-4-R1-pyrazoles are 4-(arylamino)-2-methyl-7-R-8-R1-pyrazolo[1,5- a]pyrimidine and pyrazolo[1,5- a]pyrimidine-4-thione derivatives, the ratio of which depends on the nucleophilicity of the starting 5-amino-3-R-4-R1-pyrazoles and the presence of a proton donor solvent. [ABSTRACT FROM AUTHOR]