Reaction Products of 2=Benzoy1-3-methyl- and 2-Benzoyl6-methylbenzoic Acids with Polyphosphoric A c i d

Abstract

2-Benzoy1-3-methy- and 2-benzoyl-6-methylbenzoic acid [ 2 ] in polyphosphoric acid gave 3, 3-diphenyl-7-methylphthalide [4 ]and 3, 3-dipheny1-7-[(1, 3-dihydro-4-methy1-3-oxoisobenzofuran1-yl)methy]phthalide [5] along with 1-methylanthraquinone 3 at 90-120°C, but gave only [3] at 140°C. The structure of 5 was determined by means of its MS, IR, NMR and UV spectra, and its chemical behavior. Mechanisms for the formation of [4]and [5] are discussed.