AT2433-A1, AT2433-A2, AT2433-B1 AND AT2433-B2 NOVEL ANTITUMOR COMPOUNDS PRODUCED BY ACTINOMADURA MELLIAURA

II. STRUCTURE DETERMINATION

Abstract

The chemical structures of AT2433-A1 (2), AT2433-A2 (3), AT2433-B1 (4) and AT2433-B2 (5) were elucidated by degradation and spectroscopic studies. Compounds 2-5 are disaccharides closely related to rebeccamycin. The aglycone in 2 and 3 was determined to be 6-N-methyl-11-chloro-5H-indolo[2, 3-a]pyrolo[3, 4-c]carbazole and in 4 and 5 it was determined to be 6-N-methyl-5H-indolo[2, 3-a]pyrolo[3, 4-c]carbazole. Compounds 2 and 4 are 4-N"-methyl analogs of 3 and 5.