Hydrochloric Acid → HCID 21504777, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 17 gm (0.07 mol) of 2,6,6-trimethyl3-hydroxy-6H-dibenzo-[b,d]-pyran and 14.2 gm (0.1 mol) of dimethyl acetylene-dicarboxylate in 40 ml of dioxane was admixed with a 40% solution of benzyl trimethylammonium hydroxide in water. The mixed solution was heated at 80° C for 30 minutes, cooled, admixed with 50 ml of 5 N sodium hydroxide and again heated for 1 hour at 80° C. Then, the reaction mixture was cooled, acidified with concentrated hydrochloric acid and extracted with ether. The ether extract was dried and evaporated, and the oily residue thus obtained was added slowly at room temperature to 150 ml of concentrated sulfuric acid. After standing for 1 day at room temperature, the solution was poured into ice water, and the precipitated solid substance was filtered off and heated for 3 hours in a mixture of 25 ml of acetic acid and 10 ml of concentrated hydrochloric acid. Subsequently, the mixture was evaporated to dryness, and the residue was recrystallized from methanol, yielding the compound named in the heading in the form of reddish crystals, m.p. 264°-266° C (hemihydrate).

Provenance & Evidence