Sodium Carbonate → 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-isobutyl-3,6-dioxo-1-phenyl-2-oxa-4,7,11-triazatridecan-13-oate

Participants

Reaction Steps

A solution of 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-hydroxy-propanoate (200 mg, 0.277 mmol, obtained from Reference Example 6) and [(1S)-3-methyl-1-(3-oxo-propylcarbamoyl)-butyl]-carbamic acid benzyl ester (111 mg, 0.35 mmol, obtained from Reference Example 16) in anhydrous tetrahydrofuran (4 ml) was stirred at room temperature under a nitrogen atmosphere for 15 minutes. Acetic acid (4 drops) and sodium triacetoxyborohydride (117 mg, 0.55 mmol) were added, and the resulting solution was stirred under nitrogen for an additional 3.5 hours. The reaction mixture was basified to pH 9 with sodium carbonate aqueous solution, and the aqueous layer was extracted with ethyl acetate (3×80 ml). The combined extracts were washed with saturated sodium chloride, 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-isobutyl-3,6-dioxo-1-phenyl-2-oxa-4,7,11-triazatridecan-13-oate (276 mg, 97%), as a white amorphous solid.

Provenance & Evidence