The stobbe condensation of anisaldehyde and dimethyl succinate: synthesis of the lactone of 2-carboxy-4-hydroxy-6-methoxytetralone-1

Abstract

Condensation of anisaldehyde and dimethyl succinate in presence of potassium tert.-butoxide yielded methyl hydrogen p-methoxyphenylitaconate. Reduction followed by cyclisation with polyphosphoric acid furnished 3-methoxycarbonyl-7-methoxytetralone-1 and 3-carboxy-7-methoxytetralone-1. The lactone of 1-hydroxy-3-carboxy-7-methoxy-tetralin was obtained as a product in the aluminium isopropoxide reduction of 3-methoxy-carbonyl-7-methoxytetralone-1; or by reducing the sodium salt of 3-carboxy-7-methoxytetralone-1 with sodium borohydride followed by lactonisation with dilute sulphuric acid. Oxidation of this lactone yielded the lactone of 2-carboxy-4-hydroxy-6-methoxytetralone-1.