Synthesis of boronic acid analogs of L-arginine as alternate substrates or inhibitors of nitric oxide synthase

The asymmetric synthesis of an unprotected α-amino boronic acid analog of L-arginine 1a (boroarg-OH. 2 HCl) and its Nα-acetyl derivative 1b (Ac-boroarg-OH. HCl) is described. These compounds were evaluated as substrates and inhibitors of recombinant nitric oxide synthases (NOS). Boroarg-OH 1a selectively inhibited inducible NOS (IC50 = 50 μM) compared to the neuronal isoform (IC50 = 300 μM).