Thionyl Chloride → Isoxepac
Reaction equation
[CH2:1]([O:8][C:9]1[CH:14]=[CH:13][C:12]([CH2:15][C:16]([OH:18])=[O:17])=[CH:11][C:10]=1[C:19]([OH:21])=O)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.S(Cl)(Cl)=O>>[O:21]=[C:19]1[C:7]2[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=2[CH2:1][O:8][C:9]2[CH:14]=[CH:13][C:12]([CH2:15][C:16]([OH:18])=[O:17])=[CH:11][C:10]1=2Participants
3
Procedure
A sample of 4-benzyloxy-3-carboxyphenylacetic acid is treated with an excess of thionyl chloride at reflux for 2 hours. The excess thionyl chloride is removed in vacuo and the remaining 4-benzyloxy-3-(chlorocarbonyl)phenylacetyl chloride is dissolved in methylene chloride-nitromethane and treated with an equivalent amount of aluminum chloride. The reaction mixture is stirred several hours at room temperature, refluxed for two hours and quenched with dilute hydrochloric acid. The layers are separated, the organic phase dried and evaporated in vacuo to a residue which, on crystallization from isopropyl alcohol yields 6,11-dihydro-11-oxodibenz[b,e]oxepin-2-acetic acid, mp 137°-"° C.
Workup
- temperatureat reflux for 2 hours
- customThe excess thionyl chloride is removed in vacuo