Sodium triacetoxyborohydride → 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-hydroxyethyl]-3,6-dioxo-1-phenyl-2-oxa-4,7,11-triazatridecan-13-oate

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Reaction Steps

By using an analogous procedure to that described for Example 1, a solution of [(1S,2S)-2-hydroxy-1-(3-oxo-propylcarbamoyl)-propyl]-carbamic acid benzyl ester (108 mg, 0.35 mmol, obtained from Reference Example 18), 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 (230 mg, 0.319 mmol, obtained from Reference Example 6), acetic acid (3 drops), and sodium triacetoxyborohydride (135 mg, 0.64 mmol) in anhydrous tetrahydrofuran (5 ml) was stirred under nitrogen at room temperature for 4 hours. The residue was chromatographed (flash column, silica gel, 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-hydroxyethyl]-3,6-dioxo-1-phenyl-2-oxa-4,7,11-triazatridecan-13-oate (174 mg, 54%) as a pale yellow solid.

Provenance & Evidence