Abstract
According to the Chart 1, various carboxylic acids have been prepared, in order to examine an influence of the substituting radicals upon the decarboxylation of 2-oxazolecarboxylic acids (Table I, II and III). The temperature of the decarboxylation of these carboxylic acids was measured with a silica spring thermo-balance on its loss of weight by heating every 1° per minute and the calculation was made with the linear portion of the curves obtained from the temperature and the loss of weight (Fig. 1). The temperature of the decarboxylation observed becomes higher in the following order. NO2<H<CH3O<HO<NH2 with p-substituted phenyl compounds, NO2<H<NH2 with p-substituted biphenyl compounds and except a few cases, it is found to be in accordance with the order from electron-acceptor to electron-donor. Moreover, from the residues after the temperature measurements of the decarboxylation of carboxylic acids, oxazoles have been obtained in a rich yield (Table IV).
