Reaktion #800561

Reaktionsgleichung

tetrahydro-pyran-4-one

tetrahydro-pyran-4-one

carbonic acid dimethyl ester

potassium tert-butoxide

→

title compound

Ausbeute 26.5%

4-Oxo-tetrahydro-pyran-3-carboxylic acid methyl ester

Ausbeute 26.5%

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONafter the addition
2. 2
   Sonstigehad been completely consumed
3. 3
   Sonstigethe phases were separated
4. 4
   WaschenThe organic phase was washed with water (3 L×2)
5. 5
   Extraktionthe combined aqueous phases were extracted with MTBE (2.5 L×2)
6. 6
   EinengenThe combined organic phase was concentrated under reduced pressure at 25° C.
7. 7
   Sonstigeto remove most of MTBE
8. 8
   workup.DISTILLATIONThe residue was distilled out by oil pump (˜200 Pa) at 74° C.

Vorschrift

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).

Quelle