Dichloromethane → 3-Methoxy-2-methylbenzohydrazide

Participants

Reaction Steps

To a 500 mL, 3-neck flask equipped with magnetic stirring, and chilled in an ice water bath, were added 50 mL CH2Cl2, followed by a solution of 32 g (231 mmol) K2CO3 dissolved in 80 mL water, and 24 g (479 mmol) hydrazine hydrate. Over a period of 30–60 minutes, a solution of 20 g (108.3 mmol) 2-methyl, 3-methoxybenzoyl chloride dissolved in 100 mL CH2Cl2 were added, while keeping the temperature below 10° C. The reaction mixture was stirred for an additional hour, during which time a precipitate formed. The precipitate was collected and shaken with a CH2Cl2/CHCl3 mixture; the liquid phase was separated from remaining solids, and solvent was removed in vacuo to leave 5.85 g crude product hydrazide. Meanwhile, the original CH2Cl2 solution was transferred to a separatory funnel, diluted with CHCl3, and shaken with water. The organic layer was removed, washed again with water, dried, and solvent was evaporated to leave a solid residue. This was washed thoroughly with hexane and filtered to provide an additional 6.05 g crude product hydrazide. The combined crude hydrazide was recrystallized from hot ether or ethyl acetate/hexane mixtures to yield 10.04 g 3-methoxy-2-methyl-benzoic acid hydrazide: 1H NMR (300 MHz, CDCl3) δ (ppm): 7.2 (t, 1H), 6.95 (br s, 1H), 6.9 (m, 2H), 4.15 (br s, 2H), 3.84 (s, 3H), 2.27 (s, 3H).

Provenance & Evidence