Hydrazine hydrate (1:1) → 3-Amino-2-hydroxy-N,N-dimethylbenzamide

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Reaction Steps

67.5 g of 2-Hydroxy-N,N-dimethyl-3-nitro-benzamide are dissolved in 1000 ml of EtOH/AcOH 9/1 and degassed 4× by evacuating and purging with argon. 7.5 g of Ru/C are added and the mixture obtained is degassed 4× by evacuating and purging with argon. A reaction mixture obtained is heated to reflux and 25 ml of hydrazine hydrate are added slowly. At 1 hour intervals 3 further portions of 25 ml of hydrazine hydrate are added. A reaction mixture obtained is cooled to rt, filtered and washed with EtOH. Solvent from the filtrate obtained is evaporated. Toluene is added 4× to the residue obtained and solvent is evaporated. A residue obtained is taken up in 1 l of H2O and 1 l of EtOAc. An aqueous layer obtained is extracted 3× with EtOAc. The organic layers obtained are washed 2× with brine, dried, filtered and solvent is evaporated. A residue obtained is purified by column chromatography over 500 g of silica using EtOAc/heptane 1/1 as the eluant to give 3-amino-2-hydroxy-N,N-dimethyl-benzamide.

Provenance & Evidence