Carbon Dioxide → Benzopyran

Participants

Reaction Steps

A solution was prepared by dissolving 10 g (0.0318 mole) of 5-n-octyloxy-1-hydroxy-2-acetonaphthone, 2.77 g (0.0477 mole) of acetone and 1.13 g (0.0159 mole) of pyrrolidine 100 ml of toluene, and the solution was boiled for 10 hours and water was separated. After termination of the reaction, toluene was removed under reduced pressure, and the remaining chromanone compound was dissolved in 100 ml of methanol and sodium boron hydride was gradually added to the solution to form a chromanol compound. Then, 6.0 g of the chromanol compound was heated at 150° to 160° C. together with 4.0 g of anhydrous copper sulfate in a carbon dioxide current for 10 minutes. The obtained brown viscous liquid was purified by the chromatography on silica gel to obtain 3.8 g of a chromene compound represented by the following formula: ##STR252##

Provenance & Evidence