反应详情

Nα-Benzyloxycarbonyl (L) lysine (10 g; 35.7 mmol) in benzyl alcohol (30 cm3), toluene (30 cm3) and para toluene sulphonic acid (6.93 g) was heated under reflux. The water evolved from the reaction and from the p-toluene sulphonic acid monohydrate was collected azeotropically using a Dean and Stark apparatus. Refluxing was continued until the water was no longer collected. The reaction mixture was allowed to cool, when crystals formed. The crystals were filtered off and dried, yield=5 g. The proton magnetic resonance and infrared spectra showed this compound to be the p-toluene sulphonic acid salt of the starting material. The filtrate was poured into ether (300 cm3) forming an oil. The ether was decanted off and the oil washed with ether and dried under reduced pressure. The resultant oil slowly crystallised to afford 12 g (62%) of the title compound, ν (Nujol) 3370, 1735, 1692, 1040, 1015, 820, 745, 735, 700, 685 cm-1.

1. temperatureunder reflux
2. customwas collected azeotropically
3. temperatureRefluxing
4. customno longer collected
5. temperatureto cool
6. customwhen crystals formed
7. filtrationThe crystals were filtered off
8. customdried
9. additionThe filtrate was poured into ether (300 cm3)
10. customforming an oil
11. customThe ether was decanted off
12. washthe oil washed with ether
13. customdried under reduced pressure
14. customThe resultant oil slowly crystallised