Studies on Synthesis of 10,11-Dihydro-5H-dibenzo[a, d]cycloheptene Derivatives. II. : Synthesis and Structural Confirmation of Photocycloadducts, 8,9-Dimethoxycarbonyl-2 : 3,5 : 6-dibenzobicyclo[5.2.0] nonan-4-one and Related Compounds : Using Two-Dimensi

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The photochemical reaction of dibenzo[a, d]cyclohepten-5-one (1) with dimethyl meleate or dimethyl fumarate in dioxane under external irradiation with a 100 W high pressure Hg lamp readily afforded a cycloadduct 2a in high yield along with the stereoisomer 3a. The adducts 2a and 3a were individually subjected to hydrolysis, followed by esterification with diazomethane, to afford four isomeric compounds 4a, 5a, 6a, and 7a. The stereostructures of 6a and 7a, stereoisomers of a dibenzotricyclo compound, were elucidated on the basis of intramolecular hydrogen bonding studies, and the chemical structures of the six compounds (2a, 3a, 4a, 5a, 6a, and 7a) were investigated.Two-dimensional INADEQUATE, ^<13>C/^1H shift correlation, and ^1H-^1H nuclear Overhauser effect (NOE) experiments were performed in order to verify the stereostrcture of 2a including the conformation. Total ^<13>C and ^1H assignments of 2a have been obtained unambiguously and the stereostructure was also determined from the NOE data.
公益社団法人日本薬学会の論文
1988-02-25