v-Triazolo[4,5-d]pyrimidines (8-azapurines). Part 23. Synthesis and properties of N-alkyl-1,6-dihydro-8-azapurin-2-thiones. Migration (N → N′) of acyl group in 5-aminomethyl-4-oxamoylamino-1,2,3-triazoles

Abstract

1,6-Dihydro-7-(and 8-)methyl-8-azapurine-2-thione (1a and b) were made by the action of carbon disulphide on 4-amino-5-aminomethyl-1-(and 2)-methyl-1(and 2)H-1,2,3-triazole (2c and d) respectively. These thiones were methylated to the corresponding 2-methylthio-derivatives (5a and b), which were oxidized by manganese dioxide to 7-(and 8-)methyl-2-methylthio-8-azapurine (6a and b), and the latter was further oxidized to the sulphoxide (6c).

During attempts to prepare some 1,6-dihydro-8-azapurine-2-carboxamides, hydrogenation of 3-benzyl-(and 1-methyl-)4-oxamoylamino-3(and 1)H-1,2,3-triazole-5-carbonitrile gave the 5-aminomethyl analogues (10b and d) which underwent an unusual acid-catalysed migration of the acyl group to give 4-amino-3-benzyl-(and 1-methyl-)(5-oxamoylaminomethyl-3(and 1)H-1,2,3-triazole. Direct syntheses of these products (10a and e), and also of four related ethoxalylaminotriazoles (9a and c; 10c and f) are described. ¹H N.m.r. and i.r. spectra were recorded and are discussed.