O-QUINONOID COMPOUNDS .I. SYNTHESIS AND TAUTOMERISM OF ISOQUINOLIN-3-OLS

Isoquinolin-3-ol is prepared by reaction of methyl o-formylphenylacetate with liquid ammonia. The 1-methyl, 1-phenyl, and 1,4-diphenyl derivatives are similarly prepared. These compounds exist predominantly as the lactim tautomers in ether solution, whereas in ethanol both tautomeric forms are important. Diels-Alder and photodimerisation reactions of certain isoquinolin-3-ols are described.