Hydrochloric Acid → 4-Hydroxy-8-methoxy-1-prop-2-ynyloxy-3-(2,4,6-trimethyl-phenyl)-1,8-diaza-spiro[4.5]dec-3-en-2-one

Participants

Reaction Steps

To a solution of 1-methoxy-4-{prop-2-ynyloxy-[2-(2,4,6-trimethyl-phenyl)-acetyl]-amino}-piperidine-4-carboxylic acid methyl ester (150 mg, 0.41 mmol) in dimethylformamide (2 ml) at 0° C. was added sodium methoxide (33 mg, 0.62 mmol) in one portion and stirring continued at room temperature for 4 hours. The reaction mixture was poured on ice water, acidified to pH 5-6 with an aqueous HCl solution, saturated with sodium chloride and thoroughly extracted with ethyl acetate. The combined organic layers were washed with brine, dried over sodium sulfate and concentrated. The residue was purified by chromatography on silica gel (ethyl acetate/hexane 2:1). Yield: 14 mg of 4-hydroxy-8-methoxy-1-prop-2-ynyloxy-3-(2,4,6-trimethyl-phenyl)-1,8-diaza-spiro[4.5]dec-3-en-2-one (title compound P2ii.8) as a tan solid.

Provenance & Evidence