Pyridinium chloride → 2-Acetyl-6,7-dichloro-5-hydroxybenzo[b]thiophene
Reaction equation
[C:1]([C:4]1[S:8][C:7]2[C:9]([Cl:16])=[C:10]([Cl:15])[C:11]([O:13]C)=[CH:12][C:6]=2[CH:5]=1)(=[O:3])[CH3:2].Cl.N1C=CC=CC=1>>[C:1]([C:4]1[S:8][C:7]2[C:9]([Cl:16])=[C:10]([Cl:15])[C:11]([OH:13])=[CH:12][C:6]=2[CH:5]=1)(=[O:3])[CH3:2]Participants
3
Procedure
A mixture of 9.5 g of 2-acetyl-6,7-dichloro-5-methoxybenzo[b]thiophene and 95 g of pyridine hydrochloride is heated at 185°-200° for four and one-half hours and allowed to cool. While still fluid in nature, the reaction mixture is poured onto ice and the resulting aqueous mixture is extracted three times with ethyl acetate. The organic fractions are combined, washed one time with water, two times with 2N hydrochloric acid, dried over anhydrous magnesium sulfate and evaporated. The residue is recrystallized from acetone-hexane to give 5.1 g of 2-acetyl-6,7-dichloro-5-hydroxybenzo[b]thiophene, mp 199°-201°.