Sulfuric Acid → HCID 66864216, compound

Participants

Reaction Steps

A 1:1 mixture of methyl N-{2-[(tert-butoxycarbonyl)amino]-2-(3,5-difluorophenyl)propyl}-O-[tert-butyl(dimethyl)silyl]-2-methylserinate and propan-2-yl N-{2-[(tert-butoxycarbonyl)amino]-2-(3,5-difluorophenyl)propyl}-O-[tert-butyl(dimethyl)silyl]-2-methylserinate from Step C (10.98 g, 20.65 mmol) and sulfuric acid (15.0 mL, 281 mmol) in n-BuOH (516 mL) was heated at reflux for 2 days. Most of the n-BuOH was removed in vacuo and the residual solution was cooled in an ice bath, diluted with EtOAc (200 mL) and quenched by portionwise addition of saturated aqueous NaHCO3 solution (to pH ˜8) with stirring. The layers were separated and the aqueous layer further extracted with EtOAc (200 mL). The combined organic extracts were washed successively with water and brine, and the combined aqueous layers were then saturated with NaCl (s) and further extracted with EtOAc (2×100 mL). The combined organic extracts were dried over Na2SO4, filtered and concentrated in vacuo. Purification of the residue by silica gel chromatography, eluting with a gradient of MeOH:CH2Cl2—0:100 to 10:90 afforded the title compound. MS: m/z=271 (M+1).

Provenance & Evidence