反应详情

温度

-20 °C

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.

1. waitheld at this temperature for 2 hours
2. extractionExtraction with ethyl acetate
3. customyielded
4. washafter washing the extracts with water
5. dry with materialdrying over sodium sulphate
6. customa yellow oil which was purified on silica gel (eluent: hexane/ethyl acetate 95:5→90:10)