Acid-facilitated debenzylation of N-Boc, N-benzyl double protected 2-aminopyridinomethyl pyrrolidine derivatives

2-Aminopyridinomethyl pyrrolidines represent a class of highly potent and selective neuronal nitric oxide synthase inhibitors. Conditions for a Mitsunobu reaction of a naphthol and a hindered secondary alcohol were optimized to give good to excellent yields. A key step in the synthesis of these inhibitors is the deprotection of the benzyl group from the N-Boc and N-Bn double protected 2-aminopyridine ring at a late stage of the synthesis, which has been proven difficult in our previous syntheses. Acetic acid was found to facilitate the N-Bn deprotection.