3-Chlorobenzhydrazide is a dihedral molecule that can be classified as an antibacterial and antimycobacterial agent. The crystal x-ray diffraction study revealed that 3-chlorobenzhydrazide forms a hydrogen bond with hydroxyl groups of amino acids in proteins. This property makes it an effective antibacterial agent against Gram-positive bacteria such as staphylococci and Mycobacteria tuberculosis.
General procedure for the synthesis of 3-chlorobenzhydrazide from 3-chlorobenzoic acid: a mixture of 3-chlorobenzoic acid (0.5 g, 3.19 mmol), 1,3-dicyclohexylcarbodiimide (0.72 g, 3.51 mmol), and 4-dimethylaminopyridine (0.04 g, 0.32 mmol) in ethanol was stirred for 1.5 h at room temperature. The white solid was collected by filtration and the filtrate was diluted with dichloromethane (100 mL). The organic phase was washed sequentially with 1N sodium bisulfate solution (100 mL), saturated sodium bicarbonate solution (100 mL), water (100 mL) and brine (100 mL). The organic layer was dried with anhydrous magnesium sulfate, filtered and the filtrate was concentrated under reduced pressure. The resulting crude product was dissolved in ethanol (15 mL) and hydrazine monohydrate (0.46 mL, 9.58 mmol) was added. The reaction mixture was stirred at room temperature overnight. Subsequently, the reaction mixture was concentrated to dryness under reduced pressure. The residue was purified by silica gel column chromatography with the eluent being a dichloromethane solution of 3% methanol to give 0.29 g (53% yield) of 3-chlorobenzohydrazide as a white solid.
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