Inhibitors of nitric oxide biosynthesis

A compound of the formula:

• ##STR9## in which X is represented by cyano, cyclopropyl, 2-propyne, 2, 3-butadiene or NHR.sub.2, in which R.sub.2 is represented by H, or C.sub.1-6 alkyl;
• R is represented by an amino acid or OM in which M is represented by H, C.sub.1-6 alkyl, benzyl, phenyl, or pivoyl methyl ether;
• Z is represented by O or NR.sub.1, in which R.sub.1 is represented by H, --CF.sub.3, --CH.sub.2 CF.sub.3, or C.sub.1-6 alkyl;
• and
• W is represented by a substituent selected from the group consisting of CH.sub.2 --NH--, --(CH.sub.2).sub.2 --NH--, --NH--NH--, --CH.sub.2 --NH--NH, --CH.sub.2 --O--NH and --O--NH;
• and the pharmaceutical acceptable salts thereof;
• with the following proviso's;
• 1) that when W is --NH--NH or --(CH.sub.2).sub.2 --NH-- then Z must be represented by O, and
• 2) that when X is --NHR.sub.2 and Z is --NHR.sub.1 then R.sub.1 and R.sub.2 must t be represented by the same C.sub.1-6 alkyl substituent, and
• 3) that when Z is represented by O and X is represented by NR.sub.1 then W must be --CH.sub.2 --NH-- or --(CH.sub.2).sub.2 --NH--, and
• 4) that when W is represented by CH.sub.2 --NH, Z is represented by NH, and X is NHR.sub.2, then R.sub.2 is not represented by H.