Potassium Carbonate → HCID 59389335, compound

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Reaction Steps

The compound of Example 14 (45.6 g) was dissolved in ethanol (500 mL). To this solution, carbon disulfide (10.3 mL) and dimethylsulfuric acid (16.3 mL) were added. An aqueous solution (100 mL) of potassium hydroxide (14.5 g) was then slowly added dropwise over 1.5 hours. Subsequently, ice water was added and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine and dried over sodium sulfate. The solvent was evaporated under reduced pressure and the residue was purified by silica gel column chromatography (hexane:ethyl acetate=1:4) to give a yellow oil (6.78 g). The oily product (8.64 g) was dissolved in chloroform (200 mL). To this solution, bromoethyl acetate (6.66 mL) was added and the resulting mixture was stirred for 6 hours at room temperature. Subsequently, the solvent was evaporated and the residue was washed with diethyl ether to give a yellow oil. The oily product was dissolved in chloroform (290 mL). To the solution, potassium carbonate (20.0 g) was added and the resulting mixture was stirred for 16 hours at room temperature. Subsequently, the mixture was filtered and the solvent was evaporated. Purification of the resulting residue by silica gel column chromatography (hexane:ethyl acetate=8:1) gave an inseparable mixture of the title compound and 3-ethoxycarbonyl-2-methylthio-6-(tetrahydropyrane-2-yl oxymethyl)-pyrazolo[1,5-a]pyridine as a yellow oil (3.71 g, 0.6:1).

Provenance & Evidence