Unexpected Seven-Membered Ring Formation for Muraymycin-Type Nucleoside-Peptide Antibiotics

Abstract

Naturally occurring nucleoside-peptide antibiotics such as muraymycins or caprazamycins are of major interest for the development of novel antibacterial agents. However, the synthesis of new analogues of these natural products for structure–activity relationship (SAR) studies is challenging. In our synthetic efforts towards a muraymycin-derived nucleoside building block suitable for attachment to a solid support, we came across an interesting side product. This compound resulted from an undesired Fmoc deprotection with subsequent cyclization, thus furnishing a remarkable caprazamycin-like seven-membered diazepanone ring.

Editorial: Special Issue “Molecules from Side Reactions”

“…In the tenth paper, the authors focused on the synthesis of peptidyl nucleosides as antibacterial agents. During their study to prepare an intermediate to be attached to a solid support, they found an interesting side product with a seven-membered ring [11]. In the eleventh paper, the formation of an isomeric mixture of dienynes, instead of a diallene, was detected during a reduction reaction performed on the 1,1,2,2,7,7,8,8-octaethoxyocta-3,5-diyne [12].…”