Formaldehyde → 2,2-Dimethyl-6-(1H-imidazol-1-YL)benzopyran

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 20 g (0.11 mol) of 6-amino-2,2-dimethylbenzopyran and 70 g (0.91 mol) of ammonium acetate in 190 mL of acetic acid and 770 mL of MeOH at 65° C. is added dropwise over 0.5 h, a mixture of 11.1 g (0.14 mol) of formaldehyde and 20g (0.14 mol) of glyoxal. The mixture is stirred for 1 hour at 65° C., then poured onto 800 g of ice. The pH of the solution is adjusted to 10 by the addition of concentrated ammonium hydroxide. The mixture is extracted with dichloromethane (3×200 mL) and the combined organic extracts are dried with sodium sulfate, filtered and evaporated under reduced pressure. The resulting oil is subjected to chromatography on silica gel utilizing 3% methanol in dichloromethane as eluent. The eluates are analyzed utilizing thin layer chromatography and appropriate fractions are combined and evaporated to produce the title compound.

Provenance & Evidence