This work is a contribution of theoretical chemistry to the classification of some non-steroidal anti-inflammatory drugs (NSAIDs). Indeed, research on the efficacy of NSAIDs has shown that no NSAID is recognized as the most efficient anti-inflammatory drug. We have made a theoretical study of diclofenac, bromfenac and amfenac, in order to compare their efficacy from some physicochemical properties. To do this, we used the DFT and TD-DTF methods at the B3LYP/6-311+G(d, p) level theory. The lipophilicity study shows that diclofenac and bromfenac are very lipophilic. Acidity study shows that diclofenac is more acid than bromfenac and amfenac. The results from molecular orbital and the TD-DFT calculations reveal that for the three NSAIDs, the lowest energy transition is due to the excitation from HOMO to LUMO. The absorption energy corresponding to H→L transition is comparable with the energy gap value. Our findings have shown that bromfenac is more reactive than amfenac, which is more reactive than diclofenac.
The 2-phenylbenzothiazole derivatives have antitumor activities. Work has shown that these derivatives have mesomeric forms. The electrophilic centers of these mesomers form adducts with the nucleophilic centers of deoxyribonucleic acid (DNA). These adducts destroy the tumor cells and prevent the proliferation of these. In this sense, the knowledge of electrophilic sites, nucleophiles and the capacity to protonate these derivatives is therefore useful if we want to know their future in the biological environment. Using DFT/B3LYP method associated with the bases 6-31G (d, p) and 6-31+G (d, p), this work aims at determining the preferential protonation site, the electrophilic and nucleophilic centers of six 2-phenylbenzothiazole. This study also analyzes the stability of these derivatives. Calculations are carried out in gas and aqueous phases. Results show that fluorinated derivatives are the most stable. 2-(4-aminophenyl) benzothiazoles are the most reactive. The atoms carbon C 4 , C 5 and C 6 of benzothiazole ring are the most electrophilic. Interactions of these derivatives with nucleophilic centers of deoxyribonucleic acid (DNA) will probably be at these atoms. Nitrogen sp 2 (N1) of benzothiazole ring remains the most nucleophilic center and the preferential site of protonation in all the molecules studied. These results highlight the influence of the substituents on the basicity of the nitrogen sp 2 (N1) and reactivity of the 2-phenylbenzothiazole derivatives studied.
This work is a contribution of theoretical chemistry to the knowledge of 2-thioxanthine's properties. Its aim first consists in checking the chemistry's results related to the exploitation of semi-empirical methods; it provides theoretical data on the acidity of 2-thioxanthine tautomers. To do this, the DFT method with the B3LYP functional, associated with the 6-311+G(d, p) basis set was used. The aqueous phase was modelled with the Polarizable Continuum Model (PCM). The results show that in gas and aqueous phases 2-thioxanthine can exist as a mixture of four tautomers 2TX(
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