Isocoumarins. Part I. Synthesis of 4-Methylisocoumarins

Several 4-methylisocoumarin derivatives have been synthesised by cyelodehydration of the acetonyl esters of some of the \(m\)-methoxy- and \(m\)-hydrozy-benzoic acid derivatives, viz., 3-methoxybenzoic acid, 3-me­thoxy-4-methylbenzoic acid, 3-hydroxy-6-methylbenzoic acid, \(\propto\)-resorylic acid, and its dimethyl ether, using 8.5% sulphuric acid .