Trifluoroacetic acid → 3-Pyridineacetic Acid, (3aS,4R,7R,8S,9S,10R,11R,13R,15R,15aR)-10-[[2-O-Acetyl-3,4,6-trideoxy-3-(dimethylamino)-beta-D-xylo-hexopyranosyl]oxy]-11-[[(3-cyano-1H-pyrrol-1-yl)carbonyl]oxy]-4-ethyltetradecahydro-3a,7,9,11,13,15-hexamethyl-2,6,14-trioxo-2H-oxacyclotetradecino[4,3-d]oxazol-8-yl ester

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Reaction Conditions

Reaction Steps

To a mixture of compound of Example 34 (0.35 g, 0.435 mmol) and 2-formyl-4,4-dimethoxy-butyronitrile (0.30 g, 1.91 mmol) in CH3CN was added trifluoroacetic acid (0.33 mL, 4.35 mmol). The mixture was heated to 60° C. for 18 hours and additional 2-formyl-4,4-dimethoxy-butyronitrile (0.15 g, 0.186 mmol) and trifluoroacetic acid (0.15 mL, 1.95 mmol) were added. The mixture is was heated to 60° C. for 18 hours before being cooled, diluted with ethyl acetate, washed with sat. aq. NaHCO3, water, brine, and dried over MgSO4. Concentration and chromatography (silica gel, 98:2:0.3 dichloromethane/methanol/conc. NH4OH) gave 0.16 g (41%) of the title compound. MS 880 (M+H)+.

Provenance & Evidence