Allyl chloride → 2,3-Dihydro-2,5-dimethyl-4-chloro-7-nitrobenzofuran

Participants

Reaction Conditions

Reaction Steps

A mixture of 93.4 g of 4B, 750 ml of DMSO, 48 g of 50% aqueous sodium hydroxide and 45.9 g of 3-chloropropene was stirred for 8 hours at 75°-80° C., then for 16 hours at room temperature. The resulting mixture was added to 3 liters of ice water and the resulting mixture was extracted with methylene chloride. The extract was washed with water, dried (MgSO4) and evaporated to dryness. The residue, in a nitrogen atmosphere, was heated slowly to 190° C. (one hour) and held at 185°-195° C. for two hours, cooled to room temperature, and dissolved in 250 ml of acetic acid. To this solution 150 ml of 48% aqueous hydrogen bromide solution was added, and the mixture was stirred at reflux for three hours, then mixed with 2 liters of ice water, and the resulting mixture was extracted with a 1:1 v:v mixture of hexane and ether. The extract was washed with water, 5% aqueous sodium bicarbonate solution, dried (MgSO4), charcoaled and concentrated to dryness. The residue was crystallized from 500 ml of 9:1 v:v hexane/-ether mixture, giving 2,3-dihydro-2,5-dimethyl-4-chloro-7-nitrobenzofuran (4C), m.p.: 114°-116° C.

Provenance & Evidence