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(
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.
The research aims to help reduce the enormous post-harvest losses of rice or bananas in Cote d'Ivoire. It focuses on the breakdown mechanism of their starch. This process contributes to their decay. This study wants to elucidate it; to do this, it analyzes the tetra or penta saccharide reactions with the water or dioxide carbon. It calculates the geometric, energetic and spectroscopic parameters at the ONIOM level (B3LYP/6-311++G [d, p]: AM1). These quantities allow establishing that oxygen 3 2sp O represents the privileged hydrogen bond (HB) site for amylose with four or five D-glucose building blocks. They suggest 3 3sp O′ and 3 4spO′ are respectively those of amylopectin when the latter consists of four and five D-glucose synthons. They prove that amylose deteriorates before it; the degradation of starch begins with its alteration into disaccharides. It continues with that of amylopectin into tri or tetra-saccharides with four or five building blocks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.