1,3-Dibromopropane → methyl 3-[7-(3-bromopropoxy)3,4-dihydro-2-methyl-8-propyl-2H-1-benzopyran-2-yl]propanoate

Participants

Reaction Steps

To a solution of 1.7 g (5.51 mmole) of the title compound from Example 10, 1.1 ml (11 mmoles) of 1,3-dibromopropane and 1.9 g (11 mmole) of tetrabutylammonium hydrogen sulfate in 12 ml of methylene chloride was added 5.5 ml of 2M sodium hydroxide solution. The reaction mixture was heated to reflux for 15 minutes and cooled. The organic layer was separated, washed with brine, dried over sodium sulfate, filtered, and concentrated to dryness. Chromatography of the residue on silica gel using 10% ethyl acetate/hexane as eluent gave 1.8 g of the title compound as an oil. Structure assignment was confirmed by nmr and infrared spectra.

Provenance & Evidence