Propargyl bromide → 1-Methoxy-4-{prop-2-ynyloxy-[2-(2,4,6-trimethyl-phenyl)-acetyl]-amino}-piperidine-4-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-{hydroxy-[2-(2,4,6-trimethyl-phenyl)-acetyl]-amino}-1-methoxy-piperidine-4-carboxylic acid methyl ester (compound P3ii.3 obtained in analogy to preparation example 11, step 4) (500 mg, 1.37 mmol) in tetrahydrofuran (3 ml) at 0° C. was added sodium hydride (66 mg, 55% w/w dispersion in mineral oil, 1.51 mmol) in 2 portions. The reaction mixture was stirred at 0° C. for one hour, treated with propargyl bromide (202 mg, 1.65 mmol) dropwise, and further stirred at room temperature overnight. The reaction mixture was evaporated, diluted with ethyl acetate and filtered to remove salts. The filtrate was washed twice with brine, dried over sodium sulfate and concentrated. The oily residue was purified by chromatography on silica gel (ethyl acetate/hexane 1:2). Yield: 321 mg of 1-methoxy-4-{prop-2-ynyloxy-[2-(2,4,6-trimethyl-phenyl)-acetyl]-amino}-piperidine-4-carboxylic acid methyl ester (compound P3ii.4) as a colorless gum.

Provenance & Evidence