Chloroform → 3-Methoxy-2-methylbenzohydrazide

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Reaction Steps

To a 500 mL, 3-neck flask equipped with a magnetic stirrer, and chilled in an ice water bath, were added 25 mL of CH2Cl2 (significantly greater quantities can be used) and 22.5 g (450 mmol) of hydrazine hydrate, followed by a solution of 31.5 g of K2CO3 dissolved in 60 mL of water. Over a period of 30 minutes, a solution of 31 g (168 mmol) of 2-methyl, 3-methoxybenzoyl chloride dissolved in 50 mL of CH2Cl2 was added, while keeping the temperature below 5° C. The reaction mixture was allowed to warm to room temperature and then stirred for an additional 2 hours. Water (100 mL) and chloroform (150 mL) were added, the mixture was shaken in a separatory funnel, and an inorganic precipitate was filtered off. The organic layer was dried over MgSO4 and the solvent removed in vacuo to leave 30 g of crude product hydrazide. This material was slurried with heptane for 4 hours (pentane slurry gives comparable results). Filtration and residual solvent evaporation yielded 13 g of 3-methoxy-2-methyl-benzoic acid hydrazide, containing ca. 10% of diacylated material. The product could be further purified by precipitation with hot CHCl3/hexane. 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