Perchloric Acid → 1-Ethylphenoxathiin 10,10-dioxide

Participants

Reaction Steps

A solution of 1-(1-hydroxyethyl)phenoxathiin 10,10-dioxide (590.2) g) in acetic acid (5.4 L) containing 70% aqueous perchloric acid (250 mL) was blanketed with nitrogen and 65 g of Pearlman's catalyst (20% palladium hydroxide on carbon, Aldrich Chemical Co., Milwaukee, Wis.) was added. The atmosphere above the reaction mixture was replaced by successive evacuation and flushing with nitrogen, and then the nitrogen was displaced by successive evacuations and flushing with hydrogen. The reaction mixture was then stirred vigorously and hydrogen was added until no more was taken up. The catalyst was filtered off and rinsed with acetic acid. The combined acetic acid solutions were diluted to approximately 23.5 L with water and stirred overnight at room temperature. The resulting off-white solid was collected by filtration, washed with water (2 L) and dried at 50° C. in a vacuum oven, giving 1-ethylphenoxathiin 10,10-dioxide. After recrystallization from ethyl acetate/hexanes it had a melting point of 114°-115° C. Recrystallization from ethyl acetate/pentane appeared to give a different crystalline form, mp 101°-103° C.

Provenance & Evidence