反应详情

2,6-Lutidine (88 μL) followed by oxalyl chloride (32 μL) was added to a solution of N-methyl-acetamide (28 mg) in dichloromethane (3 mL) chilled in an ice bath. After stirring the solution for 15 min, 4-{(S)-1-[(S)-6-(2-hydroxy-2-methyl-propyl)-2-oxo-6-phenyl-[1,3]oxazinan-3-yl]-ethyl}-benzoic acid hydrazide (154 mg) was added and then the cooling bath was removed. The solution was stirred for 1 h and then neutralized by the addition of saturated aqueous NaHCO3 solution. The resulting mixture was extracted twice with dichloromethane and the combined extracts were dried (MgSO4) and concentrated. The residue was taken up in acetic acid (1 mL) and stirred at 120° C. for 2.5 h. After cooling to ambient temperature, the solution was concentrated under reduced pressure and the residue was purified by chromatography on silica gel (CH2Cl2/MeOH 98:2->95:5) to afford pure Example 3 and a mixture containing Example 2. Example 2 was separated by a second chromatography on silica gel (CH2Cl2/MeOH 92:8).

1. temperaturechilled in an ice bath
2. customthe cooling bath was removed
3. stirringThe solution was stirred for 1 h
4. additionneutralized by the addition of saturated aqueous NaHCO3 solution
5. extractionThe resulting mixture was extracted twice with dichloromethane
6. dry with materialthe combined extracts were dried (MgSO4)
7. concentrationconcentrated
8. stirringstirred at 120° C. for 2.5 h
9. concentrationthe solution was concentrated under reduced pressure
10. customthe residue was purified by chromatography on silica gel (CH2Cl2/MeOH 98:2->95:5)
11. customto afford pure Example 3
12. additiona mixture containing Example 2
13. customExample 2 was separated by a second chromatography on silica gel (CH2Cl2/MeOH 92:8)