Reactions of 5-amino-3-methylisoxazole-4-carboxylic acid hydrazide with carbonyl compounds: Immunological activity and QSAR studies of products

A series of 4-imino derivatives of the 5-amino-3-methylisoxazole-4-carboxyl ic acid hydrazide and 5-amino-3-methylisoxazole[5,4-6]-6,7-dihydropyrimidin e has been prepared by condensation of 5-amino-3-methylisoxazole-4-carboxyl ic acid hydrazide with carbonyl compounds. The resulting products were eval uated for their immunological activities in the models of the humoral and c ellular immune responses of mice in vivo and concanavalin A (Con A) and lip opolysaccharide (LPS) - induced splenocyte proliferation. In addition, effe cts on polyclonal antibody production by human peripheral blood cells in cu lture were investigated. For all studied compounds we carried out quantum c hemical calculations at ab initio B3LYP 6-31G(d, p) level. The stimulatory or inhibitory effects depended strongly on the origin and location of subst ituents, which is described in the conclusions and was supported by QSAR st udies.