1-Ethyl-7-benzyloxy-3,3,5-trimethyl-1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione → 1-Ethyl-7-hydroxy-3,3,5-trimethyl-1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione

Participants

Reaction Steps

20% palladium hydroxide carbon (4.00 g) was added to a methanol (400 mL) solution of 1-ethyl-7-benzyloxy-3,3,5-trimethyl-1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione (39.8 g, 113 mmol), and catalytic hydrogenation reaction was performed at room temperature at ordinary pressure. The reaction solution was filtered to remove a catalyst, and methanol was distilled off. Ethanol (120 mL) was added to the resulting residue, and the mixture was heated while stirring. After the dissolution was confirmed, water (40 mL) was added, and the mixture was heated again. After the temperature was cooled to near room temperature, stirring was performed under ice cooling for 1 hour. Precipitated crystals were then collected by filtration. The resulting crystals were washed with 50% ethanol (40 mL), and dried at 60° C., thereby obtaining 24.3 g of white, powdery 1-ethyl-7-hydroxy-3,3,5-trimethyl-1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione (yield: 82%).

Provenance & Evidence