131766-13-7 62643-29-2 7672-27-7 L-Nabe L-Ornithine, N5-(imino(nitroamino)methyl)-, phenylmethyl ester N(G)-Nitro-L-arginine-benzylester N(omega)-Nitro-L-arginine benzyl ester N(omega)-Nitroarginine benzyl ester NABE