A process for the manufacture of the heterocyclic compounds of the formula: ##SPC1## Wherein R is a hydrogen atom or a hydrocarbon radical, which comprises decarboxylating and dinitrating a compound of the formula: ##SPC2## Wherein R has the meaning stated above, and finally hydrolysing off the acyl group, and the use of the said heterocyclic compounds as diazo components in the production of azo dyestuffs.