Methods for synthesizing 1, 3-dicyanopropene, which was the starting material for the synthesis of 1, 5-diaminopentane, were studied.
β-Hydroxyglutaronitrile was prepared by the reaction between epichlorohydrin and sodium cyanide. The product was acetylated, and after the elimination of acetic acid 1, 3-dicyanopropene was obtained. The overall yield was about 50%.
1, 3-Dicyanopropene was also synthesized by the cyanation of 1, 3-dichloropropene. The yield of 1, 3-dichloropropene by the chlorination of allyl chloride under high temperature was as high as 90%. At low temperature, 1, 2, 3-trichloropropane was produced by additive chlorination of allyl chloride.
When 1, 3-dichloropropene was treated with hydrogen cyanide in the presence of calcium carbonate 1-chloro-3-cyanopropene was formed in high yield. The cyanation of 1-chloro-3-cyanopropene into 1, 3-dicyanopropene was rather difficult, but 1, 3-dicyanopropene was obtained by the cyanation of 3-chloro-1-cyanopropene, which arose from the rearrangement of 1-chloro-3-cyanopropene.
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