Hydrochloric Acid → 3-(4-Chloro-2,6-dimethyl-phenyl)-1,4-dihydroxy-8-methoxy-1,8-diaza-spiro[4.5]dec-3-en-2-one

Participants

Reaction Steps

To a suspension of 4-{[2-(4-chloro-2,6-dimethyl-phenyl)-acetyl]-hydroxy-amino}-1-methoxy-piperidine-4-carboxylic acid methyl ester (0.40 g, 1.04 mmol) in dimethylformamide (3 ml) at 0° C. was added potassium tert-butoxide (0.35 g, 3.12 mmol) in portions. After completion of the addition, stirring was continued at 0° C. for 30 minutes and at room temperature overnight. The reaction mixture was poured into cold water (0° C.), the pH adjusted to ca 5.5 by adding 1 N HCl and then thoroughly extracted with ethyl acetate (three times). The combined organic layers were washed with water and brine, dried over sodium sulfate and concentrated. The resulting crude material was purified by column chromatography on silica gel (gradient ethyl acetate/cyclohexane 1:1→ethyl acetate). Yield: 0.14 g of 3-(4-chloro-2,6-dimethyl-phenyl)-1,4-dihydroxy-8-methoxy-1,8-diaza-spiro[4.5]dec-3-en-2-one (compound P2ii.103) as a white solid.

Provenance & Evidence