反应详情

(S)-2-Amino-3-(4-benzyloxy-phenyl)-N-tert-butyl-propionamide monohydrochloride (1.74 g, 4.80 mmol, Example 2, Step A) and 3,3-dimethylbutyraldehyde (0.48 g, 4.8 mmol, Aldrich, Milwaukee, Wis.) were mixed in CH2Cl2 (24 mL). After stirring at ambient temperature under a nitrogen atmosphere for 30 minutes, the solution was cooled to 0° C. in an ice-water bath. To this solution was added sodium triacetoxyborohydride (1.53 g, 7.20 mmol). The resulting reaction mixture was stirred for 30 minutes at 0° C., followed by an additional 12 hours at ambient temperature. Saturated aqueous NaHCO3 solution (24 mL) was added to the reaction mixture, and the resulting mixture was stirred for 5 minutes. The two layers were separated, and the aqueous layer was extracted with CH2Cl2 (2×25 mL). The combined organic solution was dried over Na2SO4. TLC (50% EtOAc in Hexanes as the eluant) showed two spots with Rf values 0.87 and 0.39. The solution was concentrated in vacuo affording a viscous oil. The lower spot on the TLC (Rf=0.39) was isolated by flash chromatography (40% EtOAc in hexanes). The free amine was dissolved in 20 mL of ethyl ether and treated with ethereal HCl to afford 1.29 g (60%) of the pure titled compound as a white solid; mp 238-240° C.

1. temperaturethe solution was cooled to 0° C. in an ice-water bath
2. customThe resulting reaction mixture
3. stirringwas stirred for 30 minutes at 0° C.
4. waitfollowed by an additional 12 hours at ambient temperature
5. stirringthe resulting mixture was stirred for 5 minutes
6. customThe two layers were separated
7. extractionthe aqueous layer was extracted with CH2Cl2 (2×25 mL)
8. dry with materialThe combined organic solution was dried over Na2SO4
9. concentrationThe solution was concentrated in vacuo
10. customaffording a viscous oil