A new ring system: 3-H-pyrazolo[3,4-h]isoquinoline. An unexpected product from diazotization of an aminoisoquinoline
Abstract
Diazotization of 7-amino-5,8-dimethyl-6-thiophenylisoquinoline with sodium nitrite in acetic acid gives a mixture of 6-thiaellipticine and 5-methyl-4-thiophenyl-3H-pyrazolo[3,4-h]isoquinoline, a new heterocyclic ring system whose crystal structure is presented.