Sodium Hydroxide → (E)-3-{1'-tert-butoxycarbonyl-4-oxo-spiro[chromane-2,4'-piperidine]-6-yl}-acrylic acid

Participants

Reaction Conditions

Reaction Steps

NaOH (160 mg, 4 mmol) in H2O (2 ml) was added to a suspension of (E)-3-{1′-tert-butoxycarbonyl-4-oxo-spiro[chromane-2,4′-piperidine]-6-yl}-acrylic acid methyl ester (462 mg, 1.15 mmol, Intermediate 1, Step B) in MeOH (6 ml). The mixture was stirred at 50° C. After 2 h, MeOH was evaporated and the pH of the aqueous phase was adjusted with 1 M HCl to a pH value of 5. The resulting suspension was extracted with DCM, the organic phase dried over Na2SO4 and concentrated to give (E)-3-{1′-tert-butoxycarbonyl-4-oxo-spiro[chromane-2,4′-piperidine]-6-yl}-acrylic acid (410 mg) as a white solid.

Provenance & Evidence