The chemistry of indanones. Part I. The ring closure of 2-(4-methoxyphenyl)-3-(3-methoxyphenyl)propionic acid

Abstract

2-(4-Methoxyphenyl)-3-(3-methoxyphenyl)propionic acid (1) undergoes acid-catalysed ring closure to the corresponding 2-phenyl-1-indanone (2). We propose structures for two by-products from this reaction. The 2-phenyl-1-indanone is shown to be susceptible to auto-oxidation being converted, in the presence of air, into a mixture of the corresponding 3-phenylisocoumarin (7; R = OMe), 2-hydroxy-2-phenylindan-1-one (11), and benzyl 2-carboxyphenyl ketone (5; R = OMe).