Acetonitrile → 3-Formyl-8-(2-(cis)-hydroxy-2,3-dihydro-1-indenyloxy)-2-methyl-imidazo[1,2-a]pyridine

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Reaction Conditions

Reaction Steps

1 g of 3-formyl-2-methyl-8-(2-(trans)-methylsulfonyloxy-2,3-dihydro-1-indenyloxy)-imidazo[1,2-a]pyridine is added to a mixture of 5.1 g of anhydrous potassium acetate, 13.8 g of 1,4,7,10,13,16-hexaoxacyclooctadecan ("18-crown-6) and 100 ml of anhydrous acetonitrile, while stirring and excluding any moisture. The brownish suspension is warmed for 18 hours at 70° C. and heated for a further 10 hours under reflux. After cooling, it is poured onto water and extraction carried out several times with dichloromethane. The organic phases are washed with water, dried and the solvent stripped off in vacuo. The dark brown residue is assayed by chromotography with the mobile phase ethyl acetate/methanol=95:5 (V/V) over silica gel. After stripping off of the solvent, the residue (0.18 g) is dissolved in 3.6 ml methanol and this solution is added dropwise with stirring to a solution of 0.072 g potassium hydroxide in 1.2 ml water. Stirring continues for one hour at room temperature, water is added, the pH is adjusted with diluted acetic acid to 6 and extraction is carried out several times with dichloromethane. The organic phases are washed with water, dried and the solvent is stripped off in vacuo. 115 mg of the title compound as a yellowish residue of m.p. 171°-173° C. is obtained.

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