Methanesulfonic Acid → 2-Methyl-6-nitrochroman-4-one

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 31.2 g (139 mmol) 3-(4-nitrophenoxy)butyric acid, 139 ml methanesulfonic acid and 7 g phosphorus pentoxide was heated on the steam bath for 1.75 hours. The reaction was cooled to 23° C., poured onto 500 ml ice-water mixture and extracted with 2×200 ml diethyl ether. The combined organic extracts were washed with 2×150 ml 1N sodium hydroxide, clarified by filtration, washed with 2×50 ml water and 100 ml brine, dried over magnesium sulfate and concentrated in vacuo to give the crude product as a yellow solid, 2.9 g (10%). Recrystallization from methylene chloride and isopropyl ether gave 1.35 g (4.7%) golden platelets, m.p. 144°-145° C.

Herkunft & Nachweise