Chemical properties and immunotropic activity of the products from reaction of N-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-5H-pyrimidinesulfone)-N′-isonicotinoylhydrazide with acids and bases in aqueous media

The effect of tautomerism on the structure of products from the reaction of N-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-5H-pyrimidinesulfone)-N′-isonicotinoylhydrazide (kristafon) with acids (hydrochloric, phosphoric, acetic, oxalic, succinic, citric, hyaluronic) and bases [sodium hydroxide, triethanolamine, tris-(hydroxymethyl)aminomethane] in aqueous media has been studied using UV, IR, PMR, and 13C NMR spectroscopy techniques. The properties of kristafon are compared to those of analogous compounds containing pyridine (isonicotine hydrazide, sulfotolylisonicotine hydrazide) and pyrimidine [bis-p-(2,4-dioxo-6-methylpyrimidinyl-5-sulfonamino)-diphenylsulfone] fragments in acid–base media. It is shown that the immunotropic activity of kristafon phosphate and kristafon are improved in hyaluronic acid solution.