Triazolo [4, 5-d] pyrimidines. VI. 3-Phenyl-3H-1, 2, 3-triazolo [4, 5-d]-pyrimidine-7-carbonitrile and Related Compounds

Abstract

Nucleophilic reagents were found to react with 3-phenyl-3H-1, 2, 3-triazolo [4, 5-d]-pyrimidine-7-carbonitrile (1) in two ways, depending on the nature of the reagent. One is substitution by attack of the reagent of the carbon at the 7-position, to which the cyano group is bonded. The other is addition to the cyano group by attack of the reagent at the carbon of the cyano group. The substitution reaction occurs with amines, alkoxide ions, carbanions (active methylene compounds or ketones in the presence of sodium hydride), and the Grignard reagents, resulting in the formation of 4-alkylamino-(2), 4-alkoxy-(3), 4-substituted (4), and 4-alkyl-3-phenyl-3H-1, 2, 3-triazolo [4, 5-d] pyrimidines (5), respectively. The addition reaction occurs in the reactions with 98% sulfuric acid and with hydroxylamine, resulting in the formation of amide (6a) and amidoxime (7), respectively. The amide (6a) forms esters (8) with alcohols, in the presence of acid. The ethyl ester (8b) is hydrolyzed by ethanolic potassium hydroxide to give the acid (9). Moreover, 8b reacts with amines, hydroxylamine, and hydrazines to form amides (6b and 6c), hydroxamic acid (10), and hydrazides (11a and 11b), respectively.