BIS imine compounds containing heterocycic aminothiophenesynthesis and characterization

Aminothiophene compounds are important members of thiophene derivatives due to their chemical structure. Since the first synthesis of these compounds, research on chemical synthesis methods and their various properties has enabled many scientific and industrial applications. Schiff bases are formed as a result of the reaction of ketone or aldehyde derivative compounds and amine compounds. Schiff bases have an important place in coordination chemistry due to their structural and biological properties. These compounds are used in many fields such as paint, pharmaceutical, plastic industry and medicine. It is one of the most researched and studied compounds in recent years. Our aim in this study is to introduce new and original compounds to the literature and characterize their chemical structures. Our work takes place in two stages. In the first stage of the study, as a result of the interaction of seven ketone derivative compounds with malononitrile or its derivatives in the presence of sulfur, eight compounds known in the literature containing 2-aminothiophene groups (tert-butyl 2-amino-3-cyano-4,7-dihydrothieno[2] were produced by the Gewald method. ,3-c]pyridine-6(5H)-carboxylate (1a), 2-amino-4,7-dihydro-5H-thieno[2,3-c]pyran-3-carbonitrile (1b), 2-amino- 6-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carbonitrile (1c), methyl 2-amino-6-methyl-4,5,6,7-tetrahydrothieno[2, 3-c]pyridine-3-carboxylate (1d), 2-amino-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile (1e), ethyl 2 -amino-6-methyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate (1f), 2-amino-6-ethyl-4,5,6,7-tetrahydrobenzo[b]thiophene- 3-carbonitrile (1g), 2-amino-4-ethyl-5-methylthiophene-3-carbonitrile (1h)) were synthesized. In the second stage of the study, as a result of the reaction of the obtained 2-aminothiophene derivative compounds with terephthalaldehyde, a total of 8 new bis imine compounds (di-tert-butyl((1,4-phenylenebis(metanylidene))bis(azanilidene))bis(3-cyano-4,7-dihydrothieno[2,3-c]pyridine-6(5H)-carboxylate) (2a), ((1,4-phenylenebis(methanylidene))bis(azanillidene))bis(4,7-dihydro-5H-thieno[2,3-c]pyran-3-carbonitrile) (2b), ((1,4-phenylenebis(methanylidene))bis(azanylidene))bis(6-methyl-4,5,6,7-tetrahydrothieno [2,3-c]pyridine-3-carbonitrile) (2c), dimethyl ((1,4-phenylenebis(methanylidene))bis(azanillidene))bis(6-methyl-4,5,6,7-tetrahydrothieno[ 2,3-c]pyridine-3-carboxylate) (2d), ((1,4-phenylenebis(methanylidene))bis(azanilidene))bis(5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo-[b]thiophene-3-carbonitrile) (2e), diethyl ((1,4-phenylenebis(methanylidene))bis(azanylidene))bis(6-methyl-4,5,6,7-tetrahydrobenzo- [b]thiophene-3-carboxylate) (2f), ((1,4-phenylenebis(methanylidene))bis(azanylidene))bis(6-ethyl-4,5,6,7-tetrahydrobenzo-[b]thiophene-3-carbonitrile) (2g), ((1,4-phenylenebis(metanylidene))bis(azanylidene))bis(4-ethyl-5-methylthiophene-3-carbonitrile) (2h)) were synthesized. The chemical structures of these new and original compounds were elucidated using FT-IR (Fourier Transform Infrared), 1H-NMR and 13C-APT (Nuclear Magnetic Resonance) spectroscopic methods. Additionally, one of the compounds we synthesized ((1,4-phenylenebis(metanylidene))bis(azanylidene))bis(6-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carbonitrile) (2c), ((1,4-phenylenebis(methanylidene))bis(azanilidene))bis(5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile) (2e) and ((1,4-phenylenebis(methanylidene))bis(azanylidene))bis(6-ethyl-4,5,6,7-tetrahydrobenzo-[b]thiophene-3-carbonitrile) (2g) has been examined. The study was completed successfully and the chemical structures of the compounds and the data obtained as a result of spectroscopic methods were compatible with each other. Key Terms: Bis-imine, Thiophene, Schiff base, NMR