Elucidation of the chemo- and stereoselectivity of [1+2] cycloaddition reactions between -cis-himachalene and dichlorocarbene using a multiphilic descriptor

A theoretical study of the mechanism and selectivity of [1+2] cycloaddition reactions between a-cis-himachalene and dichlorocarbene was performed using DFT B3LYP/6-311+G(d, p). Analysis of the global electrophilicity indeces shows that a-cis-himachalene behaves as a nucleophile, while dichlorocarbene behaves as an electrophile. In line with the local philicity concept, we propose a multiphilic descriptor. This descriptor is capable of simultaneously explaining the nucleophilicity and electrophilicity of the atomic sites in the molecule. The double bond of the six-membered ring is attacked when stoichiometric quantities of a-cis-himachalene and dichlorocarbene are used, while the other double bond is attacked by dichlorocarbene only when it is used in excess. The calculation of activation and reaction energies indicates that the a cycloadducts are favored both kinetically and thermodynamically

Service oriented centered e-health solution for monitoring and preventing chronic diseases

The modern and continuously changing lifestyles in almost all parts of the world resulted in an increase in the incidence of chronic diseases (CDs). To reduce risks associated with chronic diseases, health professionals are studying various clinical solutions. As a result of recent advances in sensing technology, wireless communications, and distributed communication, the monitoring of patients\u27 health condition and the elaboration of prevention plans are considered the most promising solutions for the treatment of chronic diseases. In this paper, we propose a novel framework for monitoring chronic diseases and tracking their vital signs. The framework relies on the service orientation concepts and standards to integrate various subsystems. Monitoring of subjects\u27 health condition, using various sensors and wireless devices, aims to proactively detect any risk of chronic diseases. The system will allow generating and customizing preventive plans dynamically according to the subject\u27s health profile and context while considering many impelling parameters. As a proof of concept of our monitoring and tracking schemes, we have considered a case study for which we have collected and analyzed preliminary data

The regio- and stereoselective addition of dibromocarbene and dichlorocarbene onto β-himachalene

In this work we used DFT B3LYP/6-31G (d) to study the mechanism, the regio- and stereoselectivity of the [1+2] cycloaddition reaction between β-himachalene and dihalogenocarbene. Analysis of the reactivity indices and calculation of the activation energies of the transition states showed that this reaction is stereoselectives, the treatment of β-himachalene with one equivalent of dibromocarbene leads via an exothermic reaction to the formation of a single product P1 resulting from the attack of the most substituted double bond C6=C7 of β-himachalene. Treatment of product P1 with one equivalent of dichlorocarbene leads, again via an exothermic reaction, to formation of the two products P3 and P4, but dibromocarbene does not react with the product P1 due to the high activation energy of this reaction

A theoretical investigation of the reactivity and regioselectivity of triterpene derivatives using difference local index, Parr functions.

A theoretical study of the reactivity and regioselectivity of thiosemicarbazide (TSC) condensation toward some carbonyl triterpenes was carried out using density functional theory with B3LYP/6-31G(d,p). The relative reactivity of these systems was rationalized by means of the global electrophilicity index. Positional selectivity, namely C3, C7 and C11, were evaluated using difference index Rk, Parr functions and difference of Parr function. The present study showed that the experimental results of the relative reactivity and regioselectivity of these reactions were correctly predicted using difference index Rk, Parr functions and difference of Parr function

Understanding the Regioselectivity and Reactivity of Friedel–Crafts benzoylation Using Parr Functions

A theoretical study of the reactivity and regioselectivity of some aromatic compounds in electrophilic aromatic substitution is carried out at the B3LYP/6-31G(d) computational level. The relative reactivity of these systems is rationalized by means of the global nucleophilicity index proposed by Domingo’s group. The positional selectivity, namely o, m or p, is predicted by means of the local nucleophilicity indices [Parr fonctions]. The present study shows that the experimental trends of the relative reactivities and regioselectivities of these reactions are correctly predicted using Parr fonctions

The mechanism, the chemoselectivity and the regioselectivity of the 1-Benzyl-4-ethynyl-1H-[1,2,3]triazole and 1-Azidomethyl-4-tert-butyl-benzene in [3+2] cycloaddition reactions: a DFT study

The [3 + 2] cycloaddition (32CA) reaction between the 1-Benzyl-4-ethynyl-1H-[1,2,3]triazole and 1-Azidomethyl-4-tert-butyl-benzen has been studied within the Density Functional Theory (DFT) B3LYP/6-311G(d,p) computational level. Analysis of the conceptual DFT reactivity indices allows the explanation of the reactivity, and the chemo- and regioselectivity experimentally observed. The possible chemoselective channels and ortho/meta regioselective channels were explored and characterized. Analysis of the energies associated with the different reaction pathways indicates that the 32CA reactions of the between the 1-benzyl-4-ethynyl-1H-[1,2,3]triazole and 1-azidomethyl-4-tert-butyl-benzene is highly chemioselective and meta regioselectivitie, in agreement with the experimental outcomes

A theoretical study of regio and stereoselectivity nitration of thymol and carvacrol using DFT approach

This work is a detailed theoretical study of the nitration aromatic substitution reactions of thymol and carvacrol. In this process, a mixture of nitric and sulfuric acids is used to produce the nitronium agent NO2+. The computational calculations were performed at the Gaussian 09 using the DFT approaches. The first task of the computing study was to determine the optimized geometry of these compounds using the Becke three-parameter hybrid exchange functional and the Lee-Yang-Parr correlation functional (B3LYP) with the 6-311+G (d, p) basis set. Geometry optimization calculations have been carried out to find the global and local minima for reactants and intermediates, respectively, and to locate the saddle points for the transition states. The vibration frequencies have been calculated in order to check the character of the stationary points obtained after the geometry optimization. It is expected only positive frequencies for reactants, intermediates and products, but only one negative imaginary frequency for transition states.The analysis of the nucleophilic fk- Fukui Function and Pk- Parr functions allows characterising the C4 carbon atom as the most nucleophilic center of thymol and carvacrol, in clear agreement with the regioselectivity obtained. Calculation of activation energies, analysis of the potential energy surface and the Gibbs free energy indicates that this reaction takes place through a two-step mechanism

Acute toxicity of essential oils of two Moroccan endemic species: Thymus broussonetii and Thymus leptobotrys

Abstract Thymus species essential oils are widely used in aromatherapy to treat several ailments. However, there is no report on their safety. In this study, we propose to investigate the acute toxicity of T. leptobotrys and T. broussonetii essential oils. These two species were selected on the basis of their frequency of medicinal use and commercial importance. Chemical analysis of these two species essential oil revealed that thymol, borneol, carvacrol and p-cymene were the main chemical constituents in T. broussonetii, whereas the essential oil of T. leptobotrys contains carvacrol (98 %) as the major component. In the acute toxicity assay, the animals showed no stereotypical symptoms associated with toxicity such as convulsion, ataxy, diarrhoea or increased diuresis. The calculated median lethal dose (LD 50 ) was estimated at 4.47 g/kg for T. broussonetii and 2.66 g/kg for T. leptobotrys

Anti-tumor properties of blackseed (Nigella sativa L.) extracts

Abstract The objective of the present study was to evaluate the in vitro and in vivo anti-cancer effect of Nigella sativa L. seed extracts. The essential oil (IC 50 = 0.6%, v/v) and ethyl acetate (IC 50 = 0.75%) extracts were more cytotoxic against the P815 cell line than the butanol extract (IC 50 = 2%). Similar results were obtained with the Vero cell line. Although all extracts had a comparable cytotoxic effect against the ICO1 cell line, with IC 50 values ranging from 0.2 to 0.26% (v/v), tests on the BSR cell line revealed a high cytotoxic effect of the ethyl acetate extract (IC 50 = 0.2%) compared to the essential oil (IC 50 = 1.2%). These data show that the cytotoxicity of each extract depends on the tumor cell type. In vivo, using the DBA2/P815 (H 2 d ) mouse model, our results clearly showed that the injection of the essential oil into the tumor site significantly inhibited solid tumor development. Indeed, on the 30th day of treatment, the tumor volume of the control animals was 2.5 ± 0.6 cm 3 , whereas the tumor volumes of the essential oil-treated animals were 0.22 ± 0.1 and 0.16 ± 0.1 cm 3 when the animals were injected with 30 µL (28.5 mg)/mouse and 50 µL (47.5 mg)/mouse per 48 h (six times), respectively. Interestingly, the administration of the essential oil into the tumor site inhibited the incidence of liver metastasis development and improved mouse survival. Correspondence A. Zya

Anti-tumor properties of black seed (Nigella Sativa)extract

Abstract The objective of the present study was to evaluate the in vitro and in vivo anti-cancer effect of Nigella sativa L. seed extracts. The essential oil (IC 50 = 0.6%, v/v) and ethyl acetate (IC 50 = 0.75%) extracts were more cytotoxic against the P815 cell line than the butanol extract (IC 50 = 2%). Similar results were obtained with the Vero cell line. Although all extracts had a comparable cytotoxic effect against the ICO1 cell line, with IC 50 values ranging from 0.2 to 0.26% (v/v), tests on the BSR cell line revealed a high cytotoxic effect of the ethyl acetate extract (IC 50 = 0.2%) compared to the essential oil (IC 50 = 1.2%). These data show that the cytotoxicity of each extract depends on the tumor cell type. In vivo, using the DBA2/P815 (H 2 d ) mouse model, our results clearly showed that the injection of the essential oil into the tumor site significantly inhibited solid tumor development. Indeed, on the 30th day of treatment, the tumor volume of the control animals was 2.5 ± 0.6 cm 3 , whereas the tumor volumes of the essential oil-treated animals were 0.22 ± 0.1 and 0.16 ± 0.1 cm 3 when the animals were injected with 30 µL (28.5 mg)/mouse and 50 µL (47.5 mg)/mouse per 48 h (six times), respectively. Interestingly, the administration of the essential oil into the tumor site inhibited the incidence of liver metastasis development and improved mouse survival