Benzene → 3-hydroxy-4-acetyl-6,6-di-propyl-6H-dibenzo-[b,d]-pyran

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Reaction Steps

The starting compound was prepared as follows: A solution of 0.3 mol of propyl magnesium iodide in 150 ml of ether was admixed all at once with a suspension of 16.6 gm (0.065 mol) of 3-hydroxy-4-acetyl-6-oxo-6H-dibenzo-[b,d]-pyran (prepared analogous to Example 7) in 300 ml of benzene. The resulting mixture was heated for 3 hours and subsequently decomposed by addition of 500 ml of water containing 25 ml of concentrated sulfuric acid. The organic phase was separated, the aqueous phase was extracted with ether, and the combined extracts were dried over sodium sulfate. After evaporation of the solvent, the residue was dissolved in 100 ml of dry benzene, treated for 15 minutes with borontrifluoride, and then poured into 2 N sodium hydroxide. After acidification with 2 N hydrochloric acid, the reaction mixture was extracted with ether, the extract was evaporated, and the residue was chromatographed on silicic acid, yielding 5.0 gm (= 23.5% of theory) of 3-hydroxy-4-acetyl-6,6-di-propyl-6H-dibenzo-[b,d]-pyran, m.p. 83°-83.5° C.

Provenance & Evidence