Ethyl Acetate → rac-3,4-Dihydro-2,5,7,8-tetramethyl-2-[(3-pyridinyl)ethynyl]-2H-1-benzopyran-6-ol

Participants

Reaction Steps

Rac-3,4-dihydro-2-ethynyl-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol, 4.6 g, was reacted as described in Example 4 with 4.74 g of 3-bromopyridine. The reaction time was extended to 18 hours. The product was isolated by chromatography over 150 g of silica gel using 10% (v/v) of ethyl acetate in methylene chloride for elution. Crystallization of the combined clean fractions from ethyl acetate/hexane gave off-white crystals with m.p. 172°-175° C. The analytical sample was recrystallized from tetrahydrofuran/hexane and had m.p. 175°-178° C.

Provenance & Evidence