Thionyl Chloride → (1-Chloroethyl)-2,4-hexadienoate

A mixture of 5.6 g. (50 mmoles) of sorbic acid and 7.8 g. (65 mmoles) of thionyl chloride was stirred at a room temperature for one hour, and then reacted at 50° C. for 30 minutes with stirring to complete the reaction. The end point of the reaction was judged by cessation of SO2 gas production and disappearance (dissolution) of sorbic acid. The resulting reaction mixture was cooled with ice, and then 0.27 g. (2 mmoles) of 96% zinc chloride was added thereto. After adding dropwise 2.2 g. of paraldehyde at 0° C., the reaction was carried out at a room temperature for one hour. The resulting reaction mixture was treated and purified in the same manner as in Reference Example 1 to give 5.43 g. (yield: 64.2%) of the desired compound being a clear solution.