Treatment of isoquinolinecarboxamide 4a
with triethyl orthoformate, chloroacetyl chloride or
carbon disulfide afforded the pyrimidinone 7, oxopyrimidinethione
12 and chloromethylpyrimidinone 18,
respectively. These products were used as versatile starting
materials for synthesis of other heterocyclic compounds.
The heterocyclic hydrazide 6 was also obtained.