Carbon‐13 and proton NMR spectra of 1(2H)‐isoquinolinone, 1(2H)‐phthalazinone, 4(3H)‐quinazolinone and their substituted derivatives

Abstract The 13 C NMR chemical shifts, one‐bond and some long‐range 13 C– 1 H coupling constants and the 1 H NMR chemical shifts for isoquinolinone, phthalazinone, quinazolinone and their derivatives containing CH 3 , COOH, COOCH 3 and CH 2 COOH substituents in the hetero‐ring are reported. The NMR data are in agreement with the lactam structure for all compounds studied; no evidence for the detectable presence of other tautomers was obtained.