Hydrochloric Acid → 1-Benzothiophene-3-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To a solution of 17 ml of a 1.6M solution of n-butyl lithium in hexane and 100 ml of dry diethyl ether at -70° C. was added a solution of 5.3 g of 3-bromobenzo[b]thiophene in 65 ml of diethyl ether. After stirring for about 30 minutes, 2.2 ml of dry dimethylformamide in 2.5 ml of dry diethyl ether were added. The mixture was stirred for about 3.5 hours at -70° C., and then allowed to warm to -5° C. Approximately 100 ml of 1N hydrochloric acid were added and the reaction mixture was stirred at 0° C. for 15 minutes. The layers were separated and the aqueous layer was extracted with one liter of ether. The organic extracts were combined, dried over magnesium sulfate, and evaporated in vacuo. The resulting oil was held at 0° C. overnight at which time an orange solid had formed. Approximately 4.6 g of this solid was recovered and identified by proton NMR to be the desired subtitle carboxaldehyde intermediate. The carboxaldehyde intermediate was used without further purification.

Provenance & Evidence