Synthesis of N-acetylglucosaminyl and diacetylchitobiosyl amides of heterocyclic carboxylic acids as potential chitinase inhibitors

2-(Dimethylamino)oxazoline-4-carboxylic acids 5 were prepared by condensati on of binucleophilic amino acids 4 and O-ethyl-N,N-dimethylisourea 3. New h eterocyclic N-acetylglucosaminyl amides and chitobiosyl amides 8 were obtai ned by the coupling of tetraacetylglucosamine 6a or heptaacetylchitobiosyla mine 6b with acid chlorides of heterocyclic carboxylic acids 2 or 5a and su bsequent deacetylation. Based on their substitution patterns, compounds 8 w ere expected to have inhibitory activity towards chitinases. Enzyme assays showed that glycosyl amides 8 indeed were moderate inhibitors of chitinases , the diacetylchitobiosyl amides 8d-f generally having higher inhibitory ac tivities than the N-acetylglucosaminyl amide derivatives 8a-c. Inhibitory a ctivities depended on the chitinase tested.