Mitomycin関連化合物の合成研究(第1報) : 2,3-Dihydro-6-methyl-1H-pyrrolo[1,2-a]indol-1-oneの合成

抄録

Mytomycin-C (I) is an antibiotic obtained from Streptomyces caespitosus by Hata and others in 1955, and its planer structure was determined by Webb and others in 1962, but its total synthesis has not been accomplished as yet. In order to synthesize the fundamental skeleton (XIX) of Mitomycin-C, examinations were made to prepare a compound with an amino group in 7-position. The compound (V) synthesized by the method described in the literature was derived to VII by the Reissert method. An attempted indole cyclization of VII to VIII was unsuccessful and the product thereby obtained was found to be IX. IX was hydrolyzed to VI, the amino group in the latter was benzoylated to X, and the Reissert reaction of X gave, not the objective XI, but VI, identical with the product from V. VI was therefore derived to the phthalimide compound (XIII) and its Reissert reaction was carried out but the starting compound was recovered. In other words, an attempt to obtain an indolecarboxylic acid with an amino group in the 5-position of indole directly from the derivatives of VI failed completely. A compound (XVI) synthesized by the method described in literature was esterified and the pyrrolo [1, 2-a] indole ring was prepared. Condensation of XVII and methyl acrylate in the presence of alkali gave the 1-keto ester compound (XVIII) whose decarboxylation afforded XIX. Introduction of an amino group into 7-position of XIX did not materialize but the fundamental skeleton (XIX) of Mitomycin-C was obtained in a good yield.