Abstract Bromination of 4-isothiazolin-3-ones, I, gave the 4-bromo derivatives, III, in good yields, while formation of 4, 5-dibromo derivatives, IV, was much more difficult. In contrast, chlorination of I, even under mild conditions, gave primarily 4, 5-dichloro derivatives, VI, and lesser amounts of the 4-chloro derivatives, V. Vigorous bromination of the 4-methyl analog of I gave the 5-bromo derivatives, VIII, whereas mild chlorination gave predominantly the 4, 5 ...
