Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1) → HCID 178493837, compound

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Reaction Steps

A 6 ml portion of THF solution containing 0.21 g of 2-(1,3-dihydro-2H-benzimidazol-2-ylidene)-1-[3-(1,2-dihydroxyethyl)phenyl]-3-(3-fluorophenyl)propane-1,3-dione and 0.3 g of methyl orthoacetate was mixed with 63 mg of pyridinium p-toluenesulfonate and then stirred at room temperature for about 30 minutes. After evaporation of the solvent, the residue was mixed with an appropriate amount of sodium bicarbonate aqueous solution, extracted several times with ethyl acetate, dried with anhydrous magnesium sulfate and concentrated. The thus formed residue was purified by a silica gel column chromatography to obtain 162 mg (68%) of 2-(1,3-dihydro-2H-benzimidazol-2-ylidene)-1-(3-fluorophenyl)-3-[3-(2-methoxy-2-methyl-1,3-dioxolan-4-yl)phenyl]propane-1,3-dione (Example 3-1) as a pale yellow foam from an ethyl acetate-hexane (1:2) eluate.

Provenance & Evidence