Methanol → Methyl 3-oxotetrahydrothiopyran-2-carboxylate

Participants

Reaction Steps

To a suspension of sodium (3.5 g, 0.15 mol) in dry toluene (300 mL) was added an excess of methanol (30 mL). After sodium was disappeared, the excess methanol was removed as the methanol-toluene azeotrope. When the distillation temperature had reached 105° C., Methyl 4-{[2-(methyloxy)-2-oxoethyl]thio}butanoate (28.3 g, 0.14 mol) in toluene (90 mL) was added over a period of ten mins. The methanol-toluene azeotrope was removed by distillation, after the distillation temperature rose to 106° C., the reaction mixture was cooled to room temperature. The reaction mixture was poured into a mixture of ice (100 g) and 12N HCl (20 mL). The organic layer was removed and the aqueous layer was extracted with three 60 mL portions of ether and the combined organic layers were dried over Na2SO4. After removing the solvent, 23.4 g of crude product was obtained (Yield: 96%).

Provenance & Evidence