Pyrrolidine → diethyl 3,4-dihydro-4-oxo-7-hydroxy-8-propyl-2H-1-benzopyran-2,2-dipropanoate

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Reaction Steps

A stirred solution of 12.3 g (53.5 mmol) of diethyl 4-oxopimelate, 10.4 g (53.5 mmol) of 2,4-dihydroxy-3-propylacetophenone, and 3.8 g (55 mmol) of pyrrolidine in 62 ml of toluene was refluxed under a water separator. After 4 hours, the mixture was allowed to cool. The solvent was removed under reduced pressure and the resultant oil was chromatographed on silica gel using ethyl acetate-hexane as eluent. The titled diester (4.98 g) was found to be homogeneous by thin-layer chromatography (20% by volume ethyl acetate/hexane on silica gel plates) and was used in subsequent reactions without further purification.

Provenance & Evidence