Manzamine C (1) has been synthesized from silyloxyscetylene (3) along the line: 4→5→8→18→1. The overall yields is 21%. Thr β-carboline segment (11) was obtained by the Bischler-Napieralski reaction of 14 followed by dehydregenation. By the similar procedure, the trans isomer 2 and dihydromanzamine C (21) have been synthesized.
beta-Carboline present in beta-carboline alkaloids from marine organisms was found, for the first time, to cleave DNA at the guanine site upon irradiation with UV light with a long wavelength without any additive, and beta-carboline-carbohydrate hybrid system was effective for DNA cleavage. (C) 2002 Elsevier Science Ltd. All rights reserved.