反应详情

The product obtained in Step 2 was added all at once at 0° C. to a solution of sodium hydrosulfide (40 g) in 800 ml of water with stirring under a nitrogen stream, the mixture was stirred at 0° C. for 30 minutes and then at room temperature for 1.5 hours, its pH was lowered to 2.0 with concentrated hydrochloric acid. The formed crystals were collected by filtration and washed with 300 ml of water and 200 ml of ethanol, affording 36 g of the objective compound as yellow crystals.

1. stirringthe mixture was stirred at 0° C. for 30 minutes
2. filtrationThe formed crystals were collected by filtration
3. washwashed with 300 ml of water and 200 ml of ethanol