3-Chlorobenzoic Acid → 3-Chlorobenzohydrazide

A mixture of 3-chlorobenzoic acid (0.5 g, 3.19 mmol), 1,3-diccyclohexylcarbodiimide (0.72 g, 3.51 mmol), 4-dimethylaminopyridine (0.04 g, 0.32 mmol) in ethanol was stirred at ambient temperature for 1.5 hour. The white solid was filtered off and the filtrate diluted with dichloromethane (100 mL). The organic solution was washed with 1N sodium hydrogen sulfate (100 mL), saturated sodium bicarbonate (100 mL), water (100 mL) and brine (100 mL). The organic phase was dried over anhydrous magnesium sulfate and filtered. The filtrate was concentrated in vacuo. The crude residue was dissolved in ethanol (15 mL) and treated with hydrazine monohydrate (0.46 mL, 9.58 mmol). The resulting clear solution was stirred overnight at ambient temperature. The reaction mixture was then concentrated to dryness in vacuo. Silica gel chromatography of the residue, using 3% methanol in dichloromethane, afforded 0.29 g (53%) of 3-chlorobenzhydrazide as a white solid.

1. filtrationThe white solid was filtered off
2. additionthe filtrate diluted with dichloromethane (100 mL)
3. washThe organic solution was washed with 1N sodium hydrogen sulfate (100 mL), saturated sodium bicarbonate (100 mL), water (100 mL) and brine (100 mL)
4. dry with materialThe organic phase was dried over anhydrous magnesium sulfate
5. filtrationfiltered
6. concentrationThe filtrate was concentrated in vacuo
7. dissolutionThe crude residue was dissolved in ethanol (15 mL)
8. stirringThe resulting clear solution was stirred overnight at ambient temperature
9. concentrationThe reaction mixture was then concentrated to dryness in vacuo

ORD record

ord-938aa8f428254a46a06b567afbed98e5

Source dataset

uspto-grants-2003_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06660753B2