RESUMO
The reactivity and mechanistic intricacies of azatrienes in Diels-Alder reactions have been relatively unexplored despite their intriguing potential applications. In this study, we employ Molecular Electron Density Theory to theoretically investigate the hetero-Diels-Alder reaction involving azatrienes with ethyl vinyl ether and allenyl methyl ether. Analysis of Conceptual Density Functional Theory, energetic profiles, and the topological characteristics is conducted to elucidate the reactions. The revealed mechanism manifests as a polar one-step two-stages process under kinetic control. We establish a clear relationship of between the periselectivity, regioselectivity, and stereoselectivity on one hand and the characteristics of the reactions mechanism on the other hand. The influence of weak interactions on reaction activation barriers and bonding evolution are discussed in detail. We demonstrate that substituents enhancing the reverse electron density flux facilitate the feasibility of the reactions. The results lay ground for a meticulous control of the reaction of azatriene in similar synthetic scenarios.
RESUMO
BACKGROUND: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common craniofacial malformations observed. Several studies suggest that the decrease in folate has been associated with a higher risk of NSCL/P. The present study aimed to determine the association of 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism gene with the occurrence of NSCL/P in the Moroccan population. METHODS: MTHFR C677T was genotyped in 52 Moroccan patients and 182 unrelated controls, using a PCR followed by restriction fragment length polymorphism. RESULTS: The results of the study revealed a genotypic and phenotypic distribution in equilibrium with Hardy-Weinberg's law (χ2=0.36, P=0.55). The frequency of heterozygous genotype C/T and the T allele in controls and patients were 40.7% vs 15.4% and 26%, respectively. CONCLUSION: A low association was found between the C677T polymorphism of the MTHFR gene and a risk for the development of NSCL/P in the Moroccan population (OR =0.24, P=0.0005).
RESUMO
The neurofibromatosis is a frequent and polymorphic genetic disorder. The severity is related to the complications. The degeneration of neurofibroma is a very rare complication of neurofibromatosis. In the literature, a few cases of solitary neurofibroma, which turned into a malignant tumor were reported. In our case, we described a very rare clinical case of neurofibrosarcoma in the scalp, and surgical treatment.
