反应详情

An aqueous Raney nickel paste (containing 0.5 g of metallic nickel) and 5.0 g of a 80% aqueous hydrazine hydrate solution were added dropwise to 200 g of an aqueous solution containing 19.7 g of 6-chloro-2-quinoxalinol-4-oxide and 8 g of sodium hydroxide at 40° to 50° C., and the resulting mixture was stirred at 40° to 70° C. for 5 hr, whereby the reducing reaction was terminated. The catalyst was then recovered by filtration, and 35% hydrochloric acid was added dropwise to the filtrate at 50° to 60° C. to adjust the pH to 4. The precipitated crystal was collected by filtration, washed with water and dried to give 16.2 g (yield 90%) of 6-chloro-2-quinoxalinol with melting point of not lower than 300° C.

1. customwhereby the reducing reaction
2. customwas terminated
3. filtrationThe catalyst was then recovered by filtration, and 35% hydrochloric acid
4. additionwas added dropwise to the filtrate at 50° to 60° C.
5. filtrationThe precipitated crystal was collected by filtration
6. washwashed with water
7. customdried