Ammonium Chloride → 4-Hydroxy-8-methoxy-1-(tetrahydro-furan-2-yloxy)-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-{(tetrahydro-furan-2-yloxy)-[2-(2,4,6-trimethyl-phenyl)-acetyl]-amino}-piperidine-4-carboxylic acid methyl ester (70 g, 161.1 mmol) in dimethylformamide (350 ml) at 10° C. was added sodium methoxide (26.9 g, 483.3 mmol) in four portions and stirring continued at 10° C. for 30 minutes, then at room temperature for 2 hours. The reaction mixture was poured on cold saturated aqueous ammonium chloride and thoroughly extracted with ethyl acetate (6×100 ml). The combined organic layers were washed with brine, dried over sodium sulfate, concentrated and dried in vacuo. The residue was triturated with hexane, filtered and the solid dried. Yield: 51.0 g of 4-hydroxy-8-methoxy-1-(tetrahydro-furan-2-yloxy)-3-(2,4,6-trimethyl-phenyl)-1,8-diaza-spiro[4.5]dec-3-en-2-one (title compound P2ii.18) as a tan solid, mp 144-146° C.

Provenance & Evidence