2-Methyl-s-triazolo[1,5-b]isoquinolin-5(10H)-one

Article abstract of DOI:10.1016/S0040-4020(01)97485-X

Acetamidrazone hydrochloride reacts with homophthalic anhydride to give 3-o-carboxybenzyl-5-methyl-1,2,4-triazole 1, which can be cyclised to 2-methyl-s-triazolo[1,5-b] isoquinolin-5(10H)-one 2. Reduction with lithium aluminium hydride gives 5,10-dihydro-2-methyl-s-triazolo [1,5-b] isoquinoline, while condensation with aromatic aldehydes gives 10-arylmethylene derivatives. Coupling with arenediazonium salts gives the 10-arylhydrazones of 5,10-dihydro-2-methyl-s-triazolo [1,5-b] isoquinoline-5,10-diones, while condensation with p-nitrosodimethylaniline gives the 10-imino derivative. Alkylation of 2 produces the corresponding 10,10-dialkyl derivatives.