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Paper | Regular issue | Vol 55, No. 4, 2001, pp.653-659
Published online, 1st January, 1970
DOI: 10.3987/COM-00-9137
An Efficient Method of Synthesizing Optically Pure N-Boc-4-bromo-N-methyl-1-tosyl-D-tryptophan Methyl Ester, a Key Intermediate in the Synthesis of Optically Active Ergot Alkaloids

Yuusaku Yokoyama,* Kumi Osanai, Masaharu Mitsuhashi, Kazuhiro Kondo, and Yasuoki Murakami*

*School of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan


Optically pure N-Boc-4-bromo-N-methyl-1-tosyl-D-tryptophan methyl ester (D-4), a key intermediate in the synthesis of optically active ergot alkaloids such as chanoclavine-I (7) and costaclavine (8), was prepared from N-acetyl-4-bromo-D-tryptophan (D-11) obtained from 4-bromoindole (9) and DL-serine (10) in two steps.