E, Z-5-arylmethylene-4-oxo-2-thioxo-1,3-thiazolidine and 3,3′-dithiobis-2H-1-benzopyran-2-one derivatives and their reactions with some amines

The reaction of 4-oxo-2-thioxo-1,3-thiazolidine (1) with salicylaldehyde (2) or its 5-bromo derivative (2b) in acetic acid and sodium acetate gave a mixture of E,Z-or E-5-arylmethylene-4-oxo-2-thioxo-1,3-thiazolidines (3a or b) and 3,3'-dithiobis-2H-1-benzopyran-2-ones (4a and b), respectively. Treatment of E,Z-thiazolidinone (3a) with benzylamine or morpholine in dioxane at room temperature afforded 3-benzylamino-2H-1-benzopyran-2-one (6a) or E,Z-2-thiazolin-4-one derivative (7b) together with the amine salt (8), respectively. Similar treatment of E-(3b) with benzylamine yielded the E,Z-2-thiazolin-4-one derivative (7a) and the disulfide (4b) as the major product. The disulfide (4a) reacted with benzylamine in cold dioxane to yield the disulfide derivative (10) in addition to 6a whereas in boiling dioxane in gave 2H-1-benzopyran-2-one derivatives (6a and b). On the other hand, when F,(3b) or 4a was treated with dicyclohexylamine in dioxane, it gave 4b as well as the amine salt (9) in the former case and 3-mercapto-2H-1-benzopyran-2-one (5, X=H) in the latter one. Structures of all products were evidenced by microanalytical and spectral data.