Summary 2, l-Benzisothiazole (1) on irradiation with a mercury high-pressure lamp in benzene/diethylamine yields, after acetylation, 2-acetylamino-benzaldehyde (3; Scheme 1). Similarly, irradiation of 3-chloro-2, 1-benzisothiazole (2) in benzene/diethylamine leads to a mixture of 3-dimethylamino-2, l-benzisothiazole (6a) and N, N-diethyl-thioanthranilamide (7a; Scheme 2). Benzisothiazole 6a, on irradiation, is not transformed into 7a. On the other ...