Bromine → 2-(3',5'-Dichlorophenyl)-4,4-dimethyl-5-bromomethylenoxazoline hydrobromide

N- (1',1'-dimethylpropynyl)-3,5-dichlorobenzamide (40 gm, 0.156 m) was dissolved in methylene chloride (600 ml) and bromine (25 gm, 0.156 m) in methylene chloride (100 ml) was added gradually with stirring at room temperature. After the complete addition of the bromine, the mixture was stirred for another 15 minutes and diluted with hexane (500 ml). The yellowish-white precipitate which formed was filtered and dried to yield 58 gm of 2-(3',5'-dichlorophenyl)-4,4-dimethyl-5-bromomethylenoxazoline hydrobromide. The oxazoline hydrobromide (55 gm, 0.13 m) was added to concentrated sulfuric acid (200 ml) and stirred to obtain a clear solution. Water (20 ml) was added and the mixture heated at about 50° C. for about 24 hours. The mixture was then poured into ice water (about 2000 ml) and the white precipitate which formed was filtered and dried. Recrystallization from isopropanol, ether and hexane (1:1:2) yielded 21 gm of pure product.