Hydrochloric Acid → 4-(2'-fluoro-5'-chlorophenyl)-4-oxo-2E-butenoic acid

반응식

[C:1]1(=[O:7])[O:6][C:4](=[O:5])[CH:3]=[CH:2]1.[Cl:8][C:9]1[CH:14]=[CH:13][C:12]([F:15])=[CH:11][CH:10]=1.[Cl-].[Al+3].[Cl-].[Cl-].Cl>>[F:15][C:12]1[CH:13]=[CH:14][C:9]([Cl:8])=[CH:10][C:11]=1[C:1](=[O:7])/[CH:2]=[CH:3]/[C:4]([OH:6])=[O:5]

참가 물질

반응물 4

HCID 313Hydrochloric Acid

HCID 7923Maleic Anhydride

HCID 9604Benzene, 1-chloro-4-fluoro-

HCID 6451240Aluminum(III) Chloride

생성물 1

HCID 108232704-(2'-fluoro-5'-chlorophenyl)-4-oxo-2E-butenoic acid

실험 절차

Finely pulverized maleic anhydride (3.0 g) is added portionwise to a mixture of 1-chloro-4-fluorobenzene (24.6 g) and anhydrous aluminium chloride (11.56 g). A gas bubbler is attached to the top of the condenser and the mixture is heated in an oil bath at 80°-85° C. for 2 hours at which time little hydrogen chloride gas evolution is evident. The mixture is cooled and the excess 1-chloro-4-fluorobenzene is recovered by distillation at water aspirator pressure. The resultant mixture is quenched with ice and then steam distilled to remove the last traces of the 1-chloro-4-fluorobenzene. Concentrated hydrochloric acid (10 mL) is added to the cooled mixture and the resultant solid collected by filtration (9.2 g). This material is taken up in boiling benzene (50 mL), treated with decolorizing charcoal and filtered through a celite bed. On standing overnight, the yellow solid is collected by filtration (2.45 g). A second recrystallization from benzene (40 mL) leads to 4-(2'-fluoro-5'-chlorophenyl)-4-oxo-2E-butenoic acid (2.1 g) as pure regioisomer.