反应详情

N-methylmorpholine (5.6 g), L-alanine methyl ester hydrochloride (3.9 g), HOBT (4.6 g) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (5.3 g) was added to a solution of Boc-(D)-Methionine (7 g, 0.028 mol) in dry DMF (50 ml). The mixture was stirred overnight. Solvent was removed by evaporation and the residue was partitioned between dichloromethane (100 ml) and 5% aqueous acetic acid (50 ml). On standing HOBT crystallised and was removed by filtration, and the organic layer was separated and washed with aqueous sodium bicarbonate, dried (MgSO4) and evaporated. The residue (8.5 g) was purified by flash chromatography in a sinter funnel eluting with a mixture of dichloromethane and ether (0% to 100% ether). The fractions containing product were combined and evaporated to give Boc-(D)-Met-(L)-Ala-OMe (7.2 g) as a gum which crystallised on standing; NMR (CDCl3): 1.4 (d, 3H), 1.45 (s, 9H), 1.95 (m, 1H), 2.1 (s, 3H), 2.1 (m, 1H), 2.6 (m, 2H), 3.75 (s,3H), 4.3 (bs, 1H), 4.6 (m, 1H), 5.3 (m, 1H), 6.9 (bs, 1H).

1. customSolvent was removed by evaporation
2. customthe residue was partitioned between dichloromethane (100 ml) and 5% aqueous acetic acid (50 ml)
3. customcrystallised
4. customwas removed by filtration
5. customthe organic layer was separated
6. washwashed with aqueous sodium bicarbonate
7. dry with materialdried (MgSO4)
8. customevaporated
9. customThe residue (8.5 g) was purified by flash chromatography in a sinter funnel
10. washeluting with a mixture of dichloromethane and ether (0% to 100% ether)
11. additionThe fractions containing product
12. customevaporated