摘要:The Reformatsky reaction of ethyl o-acetylbenzoate (II) with ethyl bromoacetate gave ethyl 3-methylphthalide-3-acetate (IIIa) as the product, which was led to 3-(o-car-boxyphenyl) butyric acid (I) via 3-(o-carboxyphenyl) crotonic acid (IVa). The structures of (IIIa) and (IVa) were established by means of their chemical properties and the ultraviolet and infrared absorption spectra, and it was shown that the method was valuable for the verification of each structure of the tautomerism represented by the following general formulae : [chemical formula]