Phthalic Anhydride → 2-(2-Thienylcarbonyl)benzoic acid

Participants

Reaction Steps

Aluminum chloride (58.7 g, 440 mmol, 2.2 equiv.) and dichloromethane (150 mL) were added to a round bottom flask. A solution of phthalic anhydride (29.6 g, 200 mmol, 1.0 equiv.) in dichloromethane (150 mL) was then added, and the mixture was stirred at room temperature for 30 minutes. Thiophene (15.8 mL, 200 mL, 1.0 equiv.) was added over 1 hour, after which the reaction mixture was stirred for 3 hours at room temperature. The reaction mixture was cautiously quenched with hydrochloric acid (0.2 M, 1 L), extracted with dichloromethane, and extracted with aqueous NaOH (1 N, 3×200 mL). The aqueous layer was acidified with concentrated hydrochloric acid; the solids were collected by filtration, and stirred in refluxing methanol. The suspension was filtered, and water was added to the filtrate to crystallize 1 as a colorless solid (20.7 g, 45%). 1H NMR (500 MHz, CDCl3) δ8.09 (dd, J=7.8, 0.85 Hz, 1H), 7.70 (dd, J=4.9, 1.1 Hz, 1H), 7.67 (td, J=7.5, 1.3 Hz, 1H), 7.58 (td, J=7.8, 1.3 Hz, 1H), 7.47 (dd, J=7.5, 0.90, 1H), 7.27-7.26 (m, 1H), 7.07-7.06 (m, 1H). m.p 144-145° C.

Provenance & Evidence