反应详情

(S)-2-acetoxy-3-tert-butoxycarbonylamino-pentanoic acid (1.82 mmol, 0.5 g, A) is dissolved in 30 mL dichloromethane. N-Cyclohexylcarbodiimide-N′-methylpolystyrene (3.64 mmol, 1.92 g, B) is added and the resulting reaction mixture stirred for 2 min. 4-(trifluoromethoxy)benzoic acid hydrazide (1.65 mmol, 0.363 g, C) is added and the reaction mixture stirred over night. After 16 hours LC/MS analysis still showed hydrazide. Polystyrene methyl isocyanate (1.65 mmol, 1.15 g) is added and stirring continued for eight hours. The reaction mixture is filtered under suction and the filtrate concentrated under reduced pressure. To give acetic acid (S)-2-tert-butoxycarbonylamino-1-[N′-(4-trifluoromethoxy-benzoyl)hydrazinocarbonyl]-butyl ester as a foam (0.5 g, 64%). According to LC/MS still some hydrazide present. MS: m/z=500 (M+Na+), 478 (M+H+)

1. customthe resulting reaction mixture
2. stirringthe reaction mixture stirred over night
3. stirringstirring
4. waitcontinued for eight hours
5. filtrationThe reaction mixture is filtered under suction
6. concentrationthe filtrate concentrated under reduced pressure