Structural and Vibrational Properties and NMR characterization of (2’-furyl)-imidazole Compounds

ANA E. LEDESMA; J. ZINCZUK; J. J. LÓPEZ- GONZÁLEZ; S. A. BRANDÁN

Magnetic Resonance Spectroscopy

Intech

Año: 2012; p. 167 - 182

The furylimidazoles compounds have a great importance in biochemistry and pharmacology because many of them present interesting properties. They are also found in artificial compounds, such as agrochemicals, pharmaceuticals, dyes6, plastics, solvents, photographic chemicals, electronics, corrosion inhibitors,7preservatives, and polymers. They can be used in synthetic organic chemistry as building blocks, due to their presence as key structural units in many natural products and in important pharmaceuticals. For example, the nature of the N- atoms in the imidazole molecule makes possible an extraordinary variety of reactions and this is the main reason for the great biological importance of the amino acid, histidine. Polymers of these compounds, which have potential as semi-conducting material are of great importance, because of their good thermal and chemical stability and relative ease of functionalization, which potentially permit the fine tuning of their physical and electronic properties In fact, these compounds provide one of the best studied examples of annular tautomerism, such as the 4(5)-substituted imidazoles. Recently, the theoretical and experimental studies on structure, electronic and vibrational properties for the (2’-furyl)-imidazole series were reported by us. Examination of the spectroscopic data for the each furanics molecules indicated that Nuclear Magnetic resonance spectroscopy, coupled with IR spectroscopy, was potentially the best analytical technique to provide confirmatory structural evidence for their formation. On the other hand, in general, the chemical shifts for the substituted imidazole ring, relative to the unsubstituted rings, suggest that the mesomeric effect of the five-membered rings contributes less to the interaction between two rings than does their inductive effects. It would indicate which rings is more electron-withdrawing in its overall electronic effect than the furan ring, as well as observed in the pyridine-thiophenes and furans. The downfield shifts of the 13C NMR signals for the carbon atom at the point of substitution on the imidazole ring would be explicate of the significant inductive electron-withdrawing effects of the 2-heteroaryl rings. . They are also found in artificial compounds, such as agrochemicals, pharmaceuticals, dyes6, plastics, solvents, photographic chemicals, electronics, corrosion inhibitors,7preservatives, and polymers. They can be used in synthetic organic chemistry as building blocks, due to their presence as key structural units in many natural products and in important pharmaceuticals. For example, the nature of the N- atoms in the imidazole molecule makes possible an extraordinary variety of reactions and this is the main reason for the great biological importance of the amino acid, histidine. Polymers of these compounds, which have potential as semi-conducting material are of great importance, because of their good thermal and chemical stability and relative ease of functionalization, which potentially permit the fine tuning of their physical and electronic properties In fact, these compounds provide one of the best studied examples of annular tautomerism, such as the 4(5)-substituted imidazoles. Recently, the theoretical and experimental studies on structure, electronic and vibrational properties for the (2’-furyl)-imidazole series were reported by us. Examination of the spectroscopic data for the each furanics molecules indicated that Nuclear Magnetic resonance spectroscopy, coupled with IR spectroscopy, was potentially the best analytical technique to provide confirmatory structural evidence for their formation. On the other hand, in general, the chemical shifts for the substituted imidazole ring, relative to the unsubstituted rings, suggest that the mesomeric effect of the five-membered rings contributes less to the interaction between two rings than does their inductive effects. It would indicate which rings is more electron-withdrawing in its overall electronic effect than the furan ring, as well as observed in the pyridine-thiophenes and furans. The downfield shifts of the 13C NMR signals for the carbon atom at the point of substitution on the imidazole ring would be explicate of the significant inductive electron-withdrawing effects of the 2-heteroaryl rings. . They are also found in artificial compounds, such as agrochemicals, pharmaceuticals, dyes6, plastics, solvents, photographic chemicals, electronics, corrosion inhibitors,7preservatives, and polymers. They can be used in synthetic organic chemistry as building blocks, due to their presence as key structural units in many natural products and in important pharmaceuticals. For example, the nature of the N- atoms in the imidazole molecule makes possible an extraordinary variety of reactions and this is the main reason for the great biological importance of the amino acid, histidine. Polymers of these compounds, which have potential as semi-conducting material are of great importance, because of their good thermal and chemical stability and relative ease of functionalization, which potentially permit the fine tuning of their physical and electronic properties In fact, these compounds provide one of the best studied examples of annular tautomerism, such as the 4(5)-substituted imidazoles. Recently, the theoretical and experimental studies on structure, electronic and vibrational properties for the (2’-furyl)-imidazole series were reported by us. Examination of the spectroscopic data for the each furanics molecules indicated that Nuclear Magnetic resonance spectroscopy, coupled with IR spectroscopy, was potentially the best analytical technique to provide confirmatory structural evidence for their formation. On the other hand, in general, the chemical shifts for the substituted imidazole ring, relative to the unsubstituted rings, suggest that the mesomeric effect of the five-membered rings contributes less to the interaction between two rings than does their inductive effects. It would indicate which rings is more electron-withdrawing in its overall electronic effect than the furan ring, as well as observed in the pyridine-thiophenes and furans. The downfield shifts of the 13C NMR signals for the carbon atom at the point of substitution on the imidazole ring would be explicate of the significant inductive electron-withdrawing effects of the 2-heteroaryl rings.