Photoisomerization of 2-aryl-1,2-benzidothiazol-3(2H)-ones
Abstract
Photoisomerization of the benzisothiazol-3(2H)-ones (1) gives the dibenzo[b,f][1,4]thiazepin-10(11H)-ones (4) Probably via homolytic cleavage of the S–N bond [(1)→(2)], cyclization of the biradical [(2)→(3)], followed by the formation of an aromatic ring together with 1,7-hydrogen transfer [(3)→(4)].