反应详情

To a solution of tetrahydro-pyran-4-one (1.3 kg, 12.98 mol) and carbonic acid dimethyl ester (11.69 kg, 129.8 mol) was added solid potassium tert-butoxide (1.89 kg, 16.08 mol) in portions at −10° C. over 2 h under nitrogen protection. The suspension was stirred at room temperature 10 h after the addition. LCMS (215 nm) indicated that tetrahydro-pyran-4-one had been completely consumed. The reaction was acidified by HCl (2 N) to pH 6˜7 and then the phases were separated. The organic phase was washed with water (3 L×2) and the combined aqueous phases were extracted with MTBE (2.5 L×2). The combined organic phase was concentrated under reduced pressure at 25° C. to remove most of MTBE. The residue was distilled out by oil pump (˜200 Pa) at 74° C. to give the title compound as colorless oil (545 g, 26.3%). CHN analysis: calculated (results). C, 53.16; (53.10), H, 6.37; (6.245), N, 0.00; (0.00).

1. additionafter the addition
2. customhad been completely consumed
3. customthe phases were separated
4. washThe organic phase was washed with water (3 L×2)
5. extractionthe combined aqueous phases were extracted with MTBE (2.5 L×2)
6. concentrationThe combined organic phase was concentrated under reduced pressure at 25° C.
7. customto remove most of MTBE
8. distillationThe residue was distilled out by oil pump (˜200 Pa) at 74° C.