Hydroxyiminoisoquinolin-3(2H)-ones. Part 4. Synthesis and reactions of isoquinoline-3,4-diones
Abstract
Deoximation of the 4-hydroxyimino-1 -phenyl-1,4-dihydroisoquinolin-3(2H)-ones (1), (2), and (3) with formaldehyde gave isoquinoline-3,4-diones; this reaction of the N-unsubstituted lactams (1) and (2) was found to be accompanied by hydroxymethylation of the amide group to yield compounds (4) and (5). In the presence of sodium acetate and hydroxylamine, the product from (4) was not the oxime but 3,4-dihydroxy-1 -phenylisoquinoline (14). Reduction of the dioxo derivatives (4) and (6) led to the 4-hydroxy-3-ones (7) and (8) and the 4-hydroxy-1,2,3,4-tetrahydroisoquinolines (9) and (10). The stereochemistry of the products was determined by n.m.r. spectroscopy.