Synthesis and Structure of Methanobenzocyclooctene Derivatives.
摘要:
10-Oxo-5,9-methanobenzocyclooctene-8-carboxylic acid 4a was prepared by the intramolecular cyclization of 4t-phenylcyclohexane-1r,2c-dicarboxylic acid 1a in concentrated H(2)SO(4) or in the reaction of 4t-phenylcyclohexane-1r,2c-dicarboxylic anhydride 2 in 80% H(2)SO(4). To improve the yield, the esters 3a,b were cyclized to the methanocyclooctene isomers 5a,b, in a 1:5 ratio from 3a, and in a 5:4 mixture (54%) from 3b at elevated temperature. After separation, 5a was hydrolysed, the keto group of 4a was reduced by the Wolff-Kishner method and the resulting cis and trans methylene-bridged benzocyclooctenes 6a,b (1:2) were separated. From 4a with hydrazine, the tetracyclic pyridazinone derivative 7 was obtained. The structures were determined by (1)H and (13)C NMR methods and for 4a also by X-ray crystallography.
摘要 苯与顺式-4-环己烯-1,2-二羧酸酐的加成生成c-2-苯甲酰基-t-5-苯基-r-1-环己烷甲酸(72%),或者在另一个反应中,4-苯基异构体(67%)。用双功能试剂制备含有异吲哚酮部分的饱和三环或部分饱和四环和五环杂衍生物。烯醇化和两个紧密相连的苯基促进了闭环中的顺式→反式异构化。产物的立体结构通过 1 H 和 13 C NMR 光谱确定。