1,1'-Carbonyldiimidazole → Cyclopentyl 4-(2-chloro-6-fluorophenyl)-1,4-dihydro-5-(1-imidazolylcarbonyl)-2,6-dimethylpyridine-3-carboxylate

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Reaction Steps

13.6 g (83 mmol) of carbonyldiimidazole are added to 33.0 g (83 mmol) of 4-(2-chloro-6-fluorophenyl)-3-cyclopentyloxycarbonyl-1,4-dihydro-2,6-dimethylpyridine-5-carboxylic acid in 350 ml of tetrahydrofuran and the mixture is heated to reflux for 3 h. Thin-layer chromatographic checking (silica gel, toluene/ethyl acetate 1:1) shows complete reaction, after which the reaction mixture is concentrated, the residue is taken up in ethyl acetate, and the solution is washed twice with water, dried over sodium sulphate and concentrated again. The target compound precipitates from ether in the form of white crystals of m.p. 150° C.

Provenance & Evidence