SYNTHESIS AND REACTIONS OF PYRIDINETHIONES

The push-pull systems 1 and 7 undergo regioselective cyclization with cyanothioacetamide 2 leading to pyridinethiones 3 and 8. Subsequent S- alkylation affords the alkylthio derivatives 5 and 10. Thieno[2,3-b]py ridines 6 and 11 are formed by using an alpha-CH-acidic halogen compou nd as alkylating agent, followed by Thorpe-Ziegler reaction. The cyano group in 6d and 11d can be converted into an imidazoline ring by trea tment with 1,2-diaminoethane hydrate and carbon disulfide. Structures are supported by spectral data as well as by X-ray analysis of 5d.