Methyl chloroformate → Methyl 5-(2,5-dimethoxy-3,4,6-trimethylphenyl)-2-pentynoate

Participants

Reaction Conditions

Reaction Steps

A solution of 5 g (21.5 mmol) of 1-(3-butynyl)-3,6-dimethoxy-2,4,5-trimethylbenzene in 80 ml of THF was cooled to -78° C. and treated firstly with 13.4 ml of a 1.6M n-butyllithium solution and then with 2.2 g (23.3 mmol) of methyl chloroformate. The mixture was left at -78° C. for 1 hour, then warmed to -20° C., held at this temperature for 2 hours and finally poured into saturated ammonium chloride solution. Extraction with ethyl acetate yielded, after washing the extracts with water and drying over sodium sulphate, a yellow oil which was purified on silica gel (eluent: hexane/ethyl acetate 95:5→90:10). There were obtained 3.6 g of spontaneously crystallizing methyl 5-(2,5-dimethoxy-3,4,6-trimethylphenyl)-2-pentynoate. M.P. 71°-72° C.

Provenance & Evidence