反应详情

Racemic 2-(4-carboxy-2-methylphenyl)glycine (9.2 g, 44 mmol) and D-lysine (6.43 g, 44 mmol) were dissolved in warm water (60 ml). The solution was filtered to remove trace insolubles and then diluted with methanol (200 ml) and diethyl ether (20 ml). An initial precipitate was removed by filtration and the filtrate allowed to stand. After 6 hours the supernatant was decanted from solid and the solid washed with methanol. The solid was then re-crystallised twice from water-methanol and the resulting crystals washed with water-methanol (1:1), methanol and diethyl ether. The white crystals were dried in vacuo, dissolved in water and chromatographed on ion exchange (Dowex 50×8-100 resin). The column was eluted with water, and 10% pyridine in water, fractions collected from the pyridine-water elution were combined and evaporated to dryness. The product was partially dissolved in water and freeze-dried [α]D26 at 147° C. (C=0.26) in aqueous hydrochloric acid (5M).

1. filtrationThe solution was filtered
2. customto remove trace insolubles
3. additiondiluted with methanol (200 ml) and diethyl ether (20 ml)
4. customAn initial precipitate was removed by filtration
5. customAfter 6 hours the supernatant was decanted from solid
6. washthe solid washed with methanol
7. customThe solid was then re-crystallised twice from water-methanol
8. washthe resulting crystals washed with water-methanol (1:1), methanol and diethyl ether
9. customThe white crystals were dried in vacuo
10. dissolutiondissolved in water
11. customchromatographed on ion exchange (Dowex 50×8-100 resin)
12. washThe column was eluted with water, and 10% pyridine in water, fractions
13. customcollected from the pyridine-water elution
14. customevaporated to dryness
15. dissolutionThe product was partially dissolved in water
16. dry with materialfreeze-dried [α]D26 at 147° C. (C=0.26) in aqueous hydrochloric acid (5M)