Methanesulfonic Acid → 2-Methyl-6-nitrochroman-4-one
Reaktionsgleichung
[N+:1]([C:4]1[CH:16]=[CH:15][C:7]([O:8][CH:9]([CH3:14])[CH2:10][C:11]([OH:13])=O)=[CH:6][CH:5]=1)([O-:3])=[O:2].CS(O)(=O)=O.O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O>>[CH3:14][CH:9]1[CH2:10][C:11](=[O:13])[C:6]2[C:7](=[CH:15][CH:16]=[C:4]([N+:1]([O-:3])=[O:2])[CH:5]=2)[O:8]1Komponenten
4
Reaktionsbedingungen
- Temperatur
- 23 °C
Versuchsvorschrift
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.