Protease inhibitors: Synthesis of L-alanine hydroxamate sulfonylated derivatives as inhibitors of Clostridium histolyticum collagenase

L-alanine hydroxamate derivatives were obtained by reaction of alkyl/arylsu lfonyl halides with L-alanine, followed by treatment with benzyl chloride, and conversion of the COOH moiety to the CONHOH group with hydroxylamine in the presence of carbodiimides. Other derivatives were obtained by reaction of N-benzyl-alanine with aryl isocyanates, arylsulfonyl isocyanates or ben zoyl isothiocyanate, followed by a similar conversion of the COOH to the CO NHOH moiety. The obtained compounds were assayed as inhibitors of Clostridi um histolyticum collagenase, ChC (EC 3.4.34.3), a zinc enzyme which degrade s triple helical collagen. The hydroxamate derivatives were generally 100-5 00 times more active than the corresponding carboxylates. In the series of synthesized derivatives, substitution patterns leading to the most potent C hC inhibitors were those involving perfluoroalkylsulfonyl- and substituted- arylsulfonyl moieties, such as pentafluorophenylsulfonyl, 3- and 4-protecte d-aminophenylsulfonyl-, 3- and 4-carboxy-phenylsulfonyl-, 3-trifluoromethyl -phenylsulfonyl-, or 1- and 2-naphthylsulfonyl among others. Similarly to t he matrix metalloproteinase (MMP) hydroxamate inhibitors, ChC inhibitors of the type reported here must incorporate hydrophobic moieties at the P-2' a nd P-3' sites, in order to achieve tight binding to the enzyme.