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.