Synthesis and fluorescent properties of some Furan-tagged Thieno[2,3-d]pyrimidines and Thieno[2,3-d:4,5-d']dipyrimidines

Intermolecular cyclization of pyrimidinethiol 1 with ethyl chloroacetate and chloroacetonitrile furnished thieno2,3-d]pyrimidines 2a,b . Hydrazinolysis of o-aminoester 2a gave acid hydrazide 3, which was cyclized with various electrophilic reagents including formic acid, triethyl orthoformate, acetic anhydride, p-chlorobenzaldehyde then triethyl orthoformate, carbon disulfide, and acetylacetone affording thienopyrimidine derivatives 4 to 10 . Another thienopyrimidine series could be obtained via treatment of o-aminocarbonitrile 2b with a variety of reagents giving derivatives 11 to 17 . The fluorescent measurements for a group of the synthesized compounds at room temperature demonstrated high fluorescent properties.