Selective Deoxygenation and 0-Methylation of Benanomicin A: Synthesis of 9-Deoxy-, 9-O-Methyl- and 14-0-Methylbenanomicin A

Abstract

The selective modifications of phenolic hydroxy groups in the chromophore of benanomicin A are described. Hydride reduction of 9-O-tosylate with sodium borohydride/nickel chloride led to 9-deoxybenanomicin A. Methylation of 1-O-diphenylmethylbenanomicin A diphenylmethyl ester with sodium hydride/iodomethane gave 9-O-methyl derivative and with HÜNIG'S base/diazotrimethylsilylmethane afforded the 14-O-methyl derivative. These compounds showed the diminished activity against fungi.