The methods of preparation most commonly applied to the synthesis of the isomeric ,/S-dimethylacrylic acids, tiglic (I) and angelic (II) acids, involve the elimination of water from -hydroxy-a-methylbutyric acid (1, 2, 3) or the elimination of acetic acid from 0-acetoxy-a-methylbutyric acid (4). These methods were investigated but wrere found to be relatively unsatisfactory because of difficulties in separating the isomeric acids and because of low yields. It was desirable, therefore, to develop methods of preparation in which the acids could be isolated in the pure state in relatively high yields.It was found that pure tiglic acid, the stable isomer, could be prepared in relatively large amounts by the action of 100% sulfuric acid on a-hydroxy-a-
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