Synthesis of 4-alkyl-1(2H)-phthalazinones and 4-alkyl-2,3-benzoxazin-1-ones via ring cleavage of 3-substituted N-alkylated-3-hydroxyisoindolin-1-ones

Abstract

N-Alkyl (Me, Et, i-Pr, t-Bu)-substituted phthalimdes 5a-d were easily transformed to 1(2H)-phthalazinones 8d-i and 2,3-benzoxazin-1-ones 9d,f,and j via a one-pot addition-decyclization-cyclocondensation process.