Synthesis and Reactions of Some New 3-Amino-2-substituted Thieno[2,3-b]quinolines

Reaction of 3-cyano-quinolin-2(1H)-thione (II) with ω-bromoacetophenones gave 3-amino-2-aroyl-thieno[2,3-b]quinolines (IVa-IVd). Whereas, interaction of II with chloroacetanilides yielded the corresponding thioesters Va-Vc which cyclized into 3-amino-2-arylcarbamoylthiene[2,3-b]quinolines (VIa-VIc) on treatment with ethoxide. Compounds VIa-VIc were reacted with nitrous acid, triethyl orthoformate and carbon disulfide to afford the fused polycyclic compounds VIIa-VIIc, VIIIa-VIIIc and IXa-IXc, respectively. Also treatment of IXa-IXc with ethyl iodide gave 3-ethylthio derivatives Xa-Xc. Moreover, refluxing of VIa-VIc with acetic anhydride resulted in the formation of oxazinone XI which recyclized into pyrimidinones XIIIa-XIIIc upon reaction with aromatic amines.