反应详情

The crude hydrobromide of α-amino-3-(phosphonomethyl)-2-quinoxalinepropanoic acid ethyl ester (1.4 mmole, 600 mg) was added to 1N aqueous potassium hydroxide (5.75 mL). The mixture was stirred overnight at room temperature, and then applied to an ion-exchange column (20 mL volume, Amberlite IRA 400) which had been prewashed with deionized water (40 mL). The column was washed to neutrality with deionized water, and the elution was continued with 0.5N hydrochloric acid. The acidic eluate was evaporated to dryness under reduced pressure, the residue was stripped with water (2×30 mL), benzene (2×30 mL), and dissolved in ethanol (10 mL). This solution was treated with propylene oxide (14.5 mmole, 1 mL), stirred for 30 minutes, the precipitate was collected by filtration, washed successively with cold ethanol and diethyl ether, and dried in vacuo at 85° C. The α-amino-3-(phosphonomethyl)-2-quinoxalinepropanoic acid (300 mg) melted at 176° C. with decomposition; MS (pos. FAB) 312 (MH+ ); 1H NMR (D2O, 400 MHz): δ3.29 (dd, J1 =21 Hz, J2 =6 Hz, 2H, CH2 --P), 3.69 (m, 2H, CH2), 4.41 (m, 1H, CH), 7.56 (m, 2H, ArH), 7.71 and 7.81 (m, 2H, ArH).

1. washThe column was washed to neutrality with deionized water
2. washthe elution
3. customThe acidic eluate was evaporated to dryness under reduced pressure
4. dissolutiondissolved in ethanol (10 mL)
5. stirringstirred for 30 minutes
6. filtrationthe precipitate was collected by filtration
7. washwashed successively with cold ethanol and diethyl ether
8. customdried in vacuo at 85° C