反应详情

To an ice-cooled suspension of 2.55 g of DL-α-amino-2-furylacetic acid in 35 ml of methylene chloride was added 4.81 ml of trimethylchlorosilane. To the resulting mixture was added dropwise 5.04 ml of triethylamine over a period of 10 minutes at 5° to 10° C. The reaction was allowed to proceed at 15° to 20° C. for one hour. To the reaction mixture was added over a period of 15 minutes at 5° to 10° C. 7.01 g of a mixture of 4-ethyl-2,3-dioxo-1-piperazinecarbonyl chloride and triethylamine hydrochloride, said mixture containing 58.02% of the former. The reaction was allowed to proceed at 10° to 15° C. for one hour. After addition of 20 ml of water, the reaction mixture was stirred at room temperature for one hour, then at 5° to 7° C. for 30 minutes. The precipitated crystals were collected by filtration, washed with 5 ml of methylene chloride and 5 ml of water in this order, and then dried to obtain 4.75 g of DL-α-(4-ethyl-2,3-dioxo-1-piperazinecarboxamido)-2-furylacetic acid, m.p. 179°-181° C. (decomp.), yield 85.6%.

1. additionTo the reaction mixture was added over a period of 15 minutes at 5° to 10° C
2. additioncontaining 58.02% of the former
3. waitto proceed at 10° to 15° C. for one hour
4. waitat 5° to 7° C. for 30 minutes
5. filtrationThe precipitated crystals were collected by filtration
6. washwashed with 5 ml of methylene chloride and 5 ml of water in this order
7. customdried