Multistep Synthesis of Sulfamoyl Aminopyridine Carboxamides Derivatives as Biologically Active Compounds

Abstract

Sulfonamides and carboxamide functionalities play a vital role in the pharmaceutical industry, polymer chemistry, and agrochemicals. Sulfonamide and carboxamide along with other groups exhibit excellent anti-bacterial properties. Keeping in view their biological importance, several similar compounds have been designed and synthesized using different methodologies. The aim of this research work is the synthesis of some sulfonamyl-aminopyridine-carboxamide derivatives with a variety of substituents. Sulfonamides were synthesized in the aqueous medium from different chlorosulfonyl benzoic acids by treating with different aliphatic and aromatic amines such as morpholine, pyrrolidine, cyclopropylamine, 4-chloroaniline, aniline, benzylamine etc. While carboxamides were synthesized by treating a variety of aminostilbazoles with carboxyl group-containing sulfonamides using EDC coupling. EDC coupling reagent with DMAP contribute to the activation of carboxylic acids. 4/-Aminostilbazole was synthesized by the Knoevenagel condensation reaction of 4-nitrotoluene with 3- pyridinecarboxaldehyde in the presence of sodium hydroxide as a base followed by the reduction of nitro group to amine using tin dichloride as a reducing agent. Aminopyridine based stilbazoles were synthesized by Heck coupling reaction between different bromo-aminopyridine compounds and differently substituted vinyl pyridines. The synthesized sulfonamide-carboxamide derivatives have different aryl and alkyl substituents including cyclopropyl, morpho line, pyrrolidine substituted anilines, and aminostilbazole moieties. These compounds were obtained in good yields (43-73%) and characterized by IH NMR and l3C NMR spectroscopy.