2-Cyclopropylbenzoic acids in the synthesis of phthalides and 3, 4-dihydroisocoumarins

…, TG Kutateladze, EV Trofimova, YS Shabarov…

Index: Mochalov; Fedotov; Kutateladze; Trofimova; Shabarov; Zefirov Chemistry of Heterocyclic Compounds, 1998 , vol. 34, # 3 p. 288 - 293

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Citation Number: 6

Abstract

Abstract 2-Cyclopropylbenzoic acids, under the action of strong protic acids (FSO 3 H, H 2 SO 4), are converted to 3-ethylphthalidium ions. In solutions in these inorganic acids, the 3- ethylphthalidium ions are isomerized to 3-methyl-3, 4-dihydroisocoumarinium ions. As a result, a thermodynamic equilibrium is established, with the concentrations of both types of cyclic ions depending on the nature of the substituent in the aromatic part of the substrate. ...