反应详情

To a -78° C. solution of 0.021 mol of LDA in DME (30 ml) was added a solution of 4.65 g (0.014 mol) of product of Example 6 in 20 ml of DME. The resulting solution was stirred for 10 minutes and treated with 2.7 ml (0.035 mol) of ethyl chloroformate. After stirring at -78° C. for 30 minutes the reaction mixture was warmed to room temperature in 30 minutes and poured into 50 ml of water. The mixture was extracted with ether. The ether extract was washed with 10% K2CO3, dried over CaSO4 and concentrated. The residue was first kugelrohr distilled at 0.15 torr (pot temperature 55° C.) to remove low boiling material (1.08 g), then distilled at 164°-173° C. (0.15 torr) to give 1.95 g (34.5%) of product as an oil.

1. stirringAfter stirring at -78° C. for 30 minutes the reaction mixture
2. extractionThe mixture was extracted with ether
3. extractionThe ether extract
4. washwas washed with 10% K2CO3
5. dry with materialdried over CaSO4
6. concentrationconcentrated
7. distillationdistilled at 0.15 torr (pot temperature 55° C.)
8. customto remove low boiling material (1.08 g)
9. distillationdistilled at 164°-173° C. (0.15 torr)