Phosphorus oxychloride → isopropyl 3-(N-methyl-2-pyrroyl)-5,6,7,8-tetrahydropyrrolo[1,2-a]pyridine-8-carboxylate

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Reaction Steps

A solution of 1.40 g. of N,N-dimethyl-1-methylpyrrole-2-carboxamide in 30 ml. of anhydrous dichloromethane containing 1.53 g. of phosphorous oxychloride is refluxed for 30 minutes under an argon atmosphere. To this solution is added a solution of 895 mg. of isopropyl 5,6,7,8-tetrahydropyrrolo[1,2-a]pyridine-8-carboxylate in 20 ml. of 1,2-dichloroethane. The reaction mixture is refluxed under an argon atmosphere for 50 hours, cooled to room temperature and treated with a solution of 4.1 g. of sodium acetate dissolved in 15 ml. of water. The resultant mixture is refluxed for 30 minutes further, and then cooled, the organic phase is separated and the aqueous phase extracted with chloroform. The combined organic solutions are washed with saturated sodium chloride solution (2×10 ml.), dried with anhydrous sodium sulfate and evaporated to dryness under reduced pressure. The oily residue is purified by t.l.c. using ethyl acetate:methylene chloride as eluant, to yield isopropyl 3-(N-methyl-2-pyrroyl)-5,6,7,8-tetrahydropyrrolo[1,2-a]pyridine-8-carboxylate (XIV, R=H, Q=CH 3, R2 =iC3H7, n=1).

Provenance & Evidence