1949 年 69 巻 12 号 p. 569-570
Dimethylacrylic acid was used as the material which, together with Br2, were dropped into methanol under the presence of AgNO3 to give (I). This was treated with 28% NH4OH in a sealed tube by heating to 90-100° to give (II). The methyl ester of (II) was prepared into benzoyl derivative (III) with benzoyl chloride in an ordinary manner.
This benzoyl derivative was heated over a water bath with POCl3 in anhydrous benzene solution and methyl 2-phenyl-5-dimethyl-(5, 4)-dihydro-oxazole-4-carboxylate (IV) was obtained as the cyclized product.
Saponification of this ester with 2% alcoholic potash gave the corresponding carboxyli cacid (V).
Application of P2S5 to (IV) to obtain the corresponding sulfur compound, 2-phenyl-5-dimethy-(5, 4)-dihydrothiazole-4-carboxylic acid (VI), was attempted but ended unsuccessfully.