Synthesis of protected derivatives of 3-pyrrolylalanine
Protected derivatives of 3-pyrrolylalanine (3-PA) have been synthesized starting with N-tri(isopropyl)silylpyrrole. Following formylation and Boc protection, treatment with (±)-N-(benzyloxycarbonyl)-α-phosphonoglycine trimethyl ester provided a fully protected dehydro-3-pyrrolylalanine. Reduction of the double bond and removal of the methyl ester groups yielded 3-PA protected at the α- and pyrrole nitrogens. 3-PA is only transiently stable following N-deprotection.