Starting from cyclohexanone and acrylonitrile, a four-step synthesis of the title open-chain C9 compounds is reported. An improved protocol for cyanoethylation of cyclohexanone in the presence of a catalytic amount of cyclohexylamine afforded 3-(2-oxocyclohexyl)-propanenitrile (1) in 92% yield. Cyclohexaneperoxycarboxylic acid (CHPCA) is introduced as a highly efficient reagent in the Baeyer-Villiger rearrangement of 1, yielding over 90% of 2. Pyrolysis of 2 afforded under optimized conditions 3 in 92% yield and 99% regioisomeric purity, otherwise a mixture of three unsaturated isomeric Ï-cyano nonenoic acids 3, 10 and 11 is obtained. Partial hydrogenation of 3 allowed the isolation of 4 in 90% yield. Hydrogenation of 4 at elevated hydrogen pressure gave 9-aminononanoic acid (5), whereas hydrolysis of 4 led to 1,9-nonanedioic acid (azelaic acid, 6). Both, 5 and 6 are valuable C9 monomers for the preparation of polyamides with specific properties.
从
环己酮和
丙烯腈出发,报道了一种四步合成标题开链C9化合物的改进方法。在催化量的
环己胺存在下,对
环己酮的腈乙基化反应进行了改进,以92%的产率得到3-(2-氧代环己基)-
丙腈(1)。
环己烷过氧
羧酸(CHPCA)作为一种高效试剂被引入到1的Baeyer-Villiger重排反应中,产率超过90%。2在优化条件下进行热解,得到92%产率和99%区域异构纯度的3,否则会得到三种不饱和异构的Φ-
氰基
壬烯酸3、10和11的混合物。3的部分氢化反应允许分离出4,产率为90%。在较高的氢压下对4进行氢化反应得到9-
氨基壬酸(5),而4的
水解反应则生成1,9-
壬二酸(
壬二酸,6)。5和6都是制备具有特定性能聚酰胺的有价值C9单体。