An Improved Synthesis of Substituted Indan-1-Carboxylic Acid

Abstract

Substituted indan-1-carboxylic acid compounds have been prepared by clyclisation of the phenyl succinic acid and reduction of the indanon-1-carboxylic acid with triethylsilane in trifluoracetic acid.Keyword: indan-1-carboxylic acid, anti-inflammatory, analgesic, triethylsilane Compounds containing indan or 2,3-dihydro-1H-inden-1-one ring systems have been studied recently in the context of the synthesis of compounds with anti-inflammatory and analgesic properties. Juby et al. 1 had reported that a series of indan-1carboxylic acid derivatives, especially the compound TAI-284 (Brand name, Clidanac), exhibited potent anti-inflammatory, analgesic and antipyretic activity. It was introduced as an antiinflammatory and analgesic drug in 1981. Das 2 observed that the writhing of Swiss albino mice induced by acetic acid was significantly reduced by 6-fluoro-3-oxoindan-1-carboxylic acid and 6-fluoroindan-1-carboxylic acid, in a dose dependent manner. In addition, halogen substituted 5-(indan-1'-yl)-tetrazoles prepared from substituted indan-1-carboxylic acid by Bachar 3 were also found to possess analgesic activity. The preparation of substituted indan-1-carboxylic acids has become increasingly important and we wished to develop a convenient synthetic route to indan derivatives.The synthesis of substituted indan-1-carboxylic acids reported by several workers 2,4-6 was mainly focused on a procedure starting from substituted phenylsuccinic acids (Scheme 1). This route had several weak points involving time-consuming procedures and inconvenient operations. Moreover, some * Correspondent.Scheme 1 Synthesis of substituted indan-1-carboxylic acid from the appropriate phenylsuccinic acid.Scheme 2 An improved and convenient synthesis of substituted indan-1-carboxylic acids.