In this work, we have focused our investigations on the protonation sites predilection in the benzimidazolyl- chalcones (BZC) derivatives. Particularly, we are interested in the study of geometrical and energetical pa...In this work, we have focused our investigations on the protonation sites predilection in the benzimidazolyl- chalcones (BZC) derivatives. Particularly, we are interested in the study of geometrical and energetical parameters. BZC are well known for their particularly nematicidal activity. Ten (10) BZC derivatives coded BZC-1 to BZC-10, with various larvicidal concentrations, have been selected for this work. They all are different one from another by the phenyl ring which is substituted by electron modulators such as alkyl, hydroxyl, alkoxy, aminoalkyl, halogen and nitro or replaced by the furan. Quantum chemical methods, namely HF/6-311 + G(d,p) and MPW1PW91/6- 311 + G(d,p) theory levels have been used to determine the geometrical and energetical parameters by the protonation on each heteroatom of the BZC derivative. An accuracy results with relatively less time consuming has been obtained using Hartree-Fock (HF) and Density Functional Theory methods (DFT/MPW1PW91). The calculations results allow identifying the sp<sup>2</sup> nitrogen as the preferential site of protonation in BZC derivative compounds.展开更多
Quantum chemistry methods were performed in order to characterize the chemical reactivity on series of imidazo[1,2-a]pyridinyl-chalcone (IPC). In particular, the B3LYP/6-311G(d) theory level has been used to determine...Quantum chemistry methods were performed in order to characterize the chemical reactivity on series of imidazo[1,2-a]pyridinyl-chalcone (IPC). In particular, the B3LYP/6-311G(d) theory level has been used to determine parameters which characterize the global and local reactivity on five molecules of the series. These compounds differ from one to another with the aryl groups. There are: 1-(2-methylimidazo[1,2-a]pyridin-3-yl)-3-phenylprop-2-en-1-one, 3-(4-fluorophenyl)-1-(2-methylimidazo [1,2-a]pyridin-3-yl)prop-2-en-1-one, 3-[4-(dimethylamino)phenyl]-1-(2-methylimidazo [1,2-a]pyridin- 3-yl)prop-2-en-1-one, 3-(2,4-dichlorophenyl)-1-(2-methylimidazo [1,2-a]pyridin-3-yl)prop-2-en-1-one, 3-(2,4-dichlorophenyl)-1-(2-methylimidazo [1,2-a]pyridin-3-yl)prop-2-en-1-one. All results lead to finding out that local nucleophilicity and electrophilicity of compounds are not substituent-dependant contrarily to their global nucleophilicity which prove to be more sensitive to the electron-donating character of the substituents. 3-[4-(Dimethylamino) phenyl]-1-(2-methylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-one was identified as the unique nucleophile compound by global reactivity. Respectively, the carbon atoms C5 and C14 are the prediction sites of electrophilic and nucleophilic attacks in the molecular skeleton of both molecules. Identification of interactions centres on IPC series is of great importance for organic synthesis and medicinal chemistry where the molecular hybridization strategy is very often used to improve biological activities of interesting therapeutic systems.展开更多
文摘In this work, we have focused our investigations on the protonation sites predilection in the benzimidazolyl- chalcones (BZC) derivatives. Particularly, we are interested in the study of geometrical and energetical parameters. BZC are well known for their particularly nematicidal activity. Ten (10) BZC derivatives coded BZC-1 to BZC-10, with various larvicidal concentrations, have been selected for this work. They all are different one from another by the phenyl ring which is substituted by electron modulators such as alkyl, hydroxyl, alkoxy, aminoalkyl, halogen and nitro or replaced by the furan. Quantum chemical methods, namely HF/6-311 + G(d,p) and MPW1PW91/6- 311 + G(d,p) theory levels have been used to determine the geometrical and energetical parameters by the protonation on each heteroatom of the BZC derivative. An accuracy results with relatively less time consuming has been obtained using Hartree-Fock (HF) and Density Functional Theory methods (DFT/MPW1PW91). The calculations results allow identifying the sp<sup>2</sup> nitrogen as the preferential site of protonation in BZC derivative compounds.
文摘Quantum chemistry methods were performed in order to characterize the chemical reactivity on series of imidazo[1,2-a]pyridinyl-chalcone (IPC). In particular, the B3LYP/6-311G(d) theory level has been used to determine parameters which characterize the global and local reactivity on five molecules of the series. These compounds differ from one to another with the aryl groups. There are: 1-(2-methylimidazo[1,2-a]pyridin-3-yl)-3-phenylprop-2-en-1-one, 3-(4-fluorophenyl)-1-(2-methylimidazo [1,2-a]pyridin-3-yl)prop-2-en-1-one, 3-[4-(dimethylamino)phenyl]-1-(2-methylimidazo [1,2-a]pyridin- 3-yl)prop-2-en-1-one, 3-(2,4-dichlorophenyl)-1-(2-methylimidazo [1,2-a]pyridin-3-yl)prop-2-en-1-one, 3-(2,4-dichlorophenyl)-1-(2-methylimidazo [1,2-a]pyridin-3-yl)prop-2-en-1-one. All results lead to finding out that local nucleophilicity and electrophilicity of compounds are not substituent-dependant contrarily to their global nucleophilicity which prove to be more sensitive to the electron-donating character of the substituents. 3-[4-(Dimethylamino) phenyl]-1-(2-methylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-one was identified as the unique nucleophile compound by global reactivity. Respectively, the carbon atoms C5 and C14 are the prediction sites of electrophilic and nucleophilic attacks in the molecular skeleton of both molecules. Identification of interactions centres on IPC series is of great importance for organic synthesis and medicinal chemistry where the molecular hybridization strategy is very often used to improve biological activities of interesting therapeutic systems.
