synthesis of new 10-arylthioanthralins and oxidation of thioanthralins to their corresponding sulfones

treatment of 10-bromoanthralin (1) with several thiophenols (2) gave the corresponding 10-arylthioanthralins (3) in high yields. oxidation of thioanthralins (3a-c) and (3k-m) using an excess of m-chloroperbenzoic acid gave the corresponding sulfones (4a-c) and (4k-m) in good yields. oxidation of thioanthralins (3d-f) gave a mixture of the corresponding sulfones (4d-f) and anthralin-10,10'-dehydrodimer (5). oxidation of thioanthralins (3g-j) afforded only anthralin-10,10'-dehydrodimer (5) with no evidence of sulfone.