反应详情

A solution of [2-hydroxy-3-methyl-1-(3-oxo-propylcarbamoyl)-butyl]-carbamic acid benzyl ester (175 mg, 0.519 mmol, obtained from Reference Example 14) and tert-butyl (2S,3R)-2-amino-3-[(2R,3R,4R,5R)-3,4-bis{[tert-butyl-(dimethyl)silyl]oxy}-5-(3-(4-methoxybenzyl)-2,4-dioxo-3,4-dihydro-1(2H)-pyrimidinyl)-tetrahydro-2-furanyl]-3-hydroxypropanoate (300 mg, 0.416 mmol, obtained from Reference Example 6) in anhydrous tetrahydrofuran was stirred at room temperature under a nitrogen atmosphere for 15 minutes. Acetic acid (3 drops) and sodium triacetoxyborohydride (176 mg, 0.831 mmol) were added and the resulting solution was stirred under nitrogen for an additional 2.5 hours. The reaction mixture was basified to pH 9 with aqueous sodium carbonate solution, and the aqueous layer was extracted with ethyl acetate (3×75 mL). The combined extracts were washed with saturated sodium chloride solution, dried over sodium sulfate, filtered and concentrated in vacuo. The residue was chromatographed (flash column, silica gel, 2.5% methanol in methylene chloride) to provide tert-butyl (5S,12S)-12-[(R)-[(3R,4R,5R)-3,4-bis{[tert-butyl(dimethyl)silyl]oxy}-5-(3-(4-methoxybenzyl)-2,4-dioxo-3,4-dihydro-1(2H)-pyrimidinyl)tetrahydro-2-furanyl](hydroxy)methyl]-5-[(1S)-1-hydroxy-2-methylpropyl]-3,6-dioxo-1-phenyl-2-oxa-4,7,11-triazatridecan-13-oate (258 mg, 60%) as a white amorphous solid.

1. extractionthe aqueous layer was extracted with ethyl acetate (3×75 mL)
2. washThe combined extracts were washed with saturated sodium chloride solution
3. dry with materialdried over sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customThe residue was chromatographed (flash column, silica gel, 2.5% methanol in methylene chloride)