tert-Butyl acrylate → (E)-3-{1'-Methyl-4-oxo-spiro[chromane-2,4'-piperidine]-6-yl}-acrylic acid tert-butyl ester

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Reaction Steps

(E)-3-{1′-Methyl-4-oxo-spiro[chromane-2,4′-piperidine]-6-yl}-acrylic acid tert-butyl ester was synthesized starting from 1′-methyl-6-bromo-spiro[chromane-2,4′-piperidine]-4-one (1.62 g, 5.22 mmol) according to the procedure for preparation of Intermediate 1, Step B, using tert-butylacrylate, giving a yellow solid (1.45 g). The resulting product was dissolved in a 20% TFA/DCM mixture (25 ml) and stirred at RT. After 16 h, the solvent was evaporated and the residue was partitioned between DCM and a saturated NaHCO3 solution. Then the aqueous phase was acidified with a 6 M solution of HCl and evaporated. The residue was suspended in a 9:1 DCM/MeOH mixture (70 ml) and the insoluble salts were filtered off. The solvent was dried over Na2SO4 and evaporated, giving (E)-3-{1′-methyl-4-oxo-spiro[chromane-2,4′-piperidine]-6-yl}-acrylic acid (890 mg) as a yellow solid.

Provenance & Evidence