Chloroacetaldehyde → 6-(3-Methoxy-phenyl)-7-pyridin-4-yl-2,3-dihydro-pyrazolo[5,1-b]thiazol-3-ol

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Reaction Steps

5-(3-Methoxy-phenyl)-4-pyridin-4-yl-2H-pyrazole-3-thiol prepared as described in Example 8 (115 mg, 0.406 mmol) was dissolved in a 1:1 THF/water mixture (3 mL). A 55% aqueous solution of chloroacetaldehyde (0.071 mL, 0.609 mmol, 1.5 eq) was added and the mixture was stirred at room temperature for 2 hours. It was then diluted with ethylacetate and washed with saturated aqueous NaHCO3 and brine, dried over Na2SO4 and evaporated to dryness to give 123 mg (93%) of crude product, which was used without further purification in the following step.

Provenance & Evidence