反应详情

温度

0 °C

119 ml. (1.025 moles) of benzoyl chloride and 760 ml. of 2N. sodium hydroxide solution (1.52 moles) are simultaneously added to a mixture of 100 g. (0.854 mole) of DL-valine, 200 ml. of dioxane and 350 ml. of 2N. sodium hydroxide solution (0.7 mole) stirred at 0°-5° C., the additions being at rates such that the pH of the reaction mixture is always basic and the temperature does not exceed 5° C., the reaction being exothermic. The reaction mixture is allowed to warm to 20°-25° C., stirred at 20°-25° C. for 2 hours, cooled to 0° C. and acidified with about 40 ml. of concentrated sulfuric acid. The precipitate is collected by filtration, washed with water, air dried for 16 hours and dissolved in ethyl acetate. The ethyl acetate solution is decanted from some residual water, and petroleum ether is added to obtain a precipitate. The precipitate is subjected to high vacuum for 8 hours to remove some residual dioxane and obtain the product (165.81 g. (88%)), m.p. 125°-128° C. Lit.: 132° C.

1. customdoes not exceed 5° C.
2. temperatureto warm to 20°-25° C.
3. filtrationThe precipitate is collected by filtration
4. washwashed with water, air
5. customdried for 16 hours
6. dissolutiondissolved in ethyl acetate
7. customThe ethyl acetate solution is decanted from some residual water, and petroleum ether
8. additionis added
9. customto obtain a precipitate
10. waitThe precipitate is subjected to high vacuum for 8 hours
11. customto remove some residual dioxane
12. customobtain the product (165.81 g. (88%)), m.p. 125°-128° C
13. custom132° C.