Three-Component Condencations of 3-Amino-1,2,4-triazoles, Methyl 3-(2-Cycloamino-4-methylpyrimidin-5-yl)-3-oxopropionoates, and a Series of C 1 Synthons as a Convenient Approach to Pyrimidin-5-yl-1,2,4-triazolo[1,5- a ]pyrimidines

A convenient synthetic approach to polysubstituted dihydrogenated or heteroaromatic 1,2,4-triazolo[1,5-a]pyrimidines derivatives containing at position 5 a 4-methylpyrimidine moiety bearing a cycloamino substituent at position 2 and linked to the triazolopyrimidine bicycle through its position 5 was developed. The approach involves unusual three-component condensations of 3-amino-1,2,4-triazoles, methyl 3-(2-R-4-methylpyrimidin-5-yl)-3-oxopropionates, and a series of C1 synthons whose synthetic equivalents are a series of aromatic aldehydes, triethyl orthoformate, or DMFDMA were used as of C1 synthons.