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1.
Chemistry ; 23(10): 2439-2447, 2017 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-27943478

RESUMO

The three-component free-radical carbo-alkenylation of electron-rich olefins has been studied, varying the substitution pattern in the alkene, in the radical precursor and in the final acceptor. New vinylsulfones were also prepared and their reactivity investigated. The scope and limitations of the process was established, and the reaction mechanism clarified using selected dienes as radical clocks. It was thus recognised that the reversible addition onto the olefin of the released sulfonyl group is an important event, which should not be overlooked when using such multicomponent carbo-alkenylation reactions.

2.
Front Psychol ; 13: 899557, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36033068

RESUMO

In the literature, a mass of studies have inspected the effects of computer-assisted language learning (CALL) and mobile-assisted language learning (MALL) on Iranian English as a Foreign Language (EFL) learners' achievement. However, the effects of CALL and MALL on psychological factors, such as motivation, anxiety, and self-efficacy, have largely remained unexplored. Thus, this study explored the effects of CALL and MALL, and face-to-face (FTF) learning environments on Iranian EFL learners' motivation, anxiety, and self-efficacy. To this aim, using a random sampling method, a total of 137 male EFL intermediate learners were selected and homogenized using the Oxford Quick Placement Test (OQPT). Based on the test scores, a total of 90 EFL learners were selected and randomly assigned to three groups, namely, CALL (n = 30), MALL (n = 30), and FTF (n = 30). Then, the participants' motivation, anxiety, and self-efficacy were gauged prior to the instructions. Afterward, they received CALL-based, MALL-based, and conventional instructions which lasted 25 1-h sessions held twice a week. At the end of the instructions, the participants' motivation, anxiety, and self-efficacy were measured again. The collected data were analyzed through a one-way MANOVA. Findings evidenced that the experimental groups' motivation, anxiety, and self-efficacy were positively affected by the CALL-based and MALL-based instructions. However, there was not a statistically significant difference between the CALL group and MALL group concerning the gains of motivation, anxiety, and self-efficacy. In light of the findings, a range of implications is suggested for relevant stakeholders.

3.
Org Lett ; 17(18): 4518-21, 2015 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-26348122

RESUMO

The first total synthesis of eucophylline was reported in 10 steps and 10% overall yield. The naphthyridine core of eucophylline was prepared through the coupling between a strained azabicyclo[3.3.1]nonan-2-one and a trisubstituted benzonitrile, followed by a cyclization of the corresponding amidine. This coupling reaction was shown to proceed through a stable bicyclic chloroenamine intermediate. The azabicyclo[3.3.1]nonan-2-one skeleton was in turn accessible through a straightforward sequence including a free-radical three-component olefin carbo-oximation as a key step.


Assuntos
Alcanos/síntese química , Compostos Azabicíclicos/síntese química , Alcanos/química , Alcenos , Apocynaceae/química , Compostos Azabicíclicos/química , Ciclização , Radicais Livres , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Estereoisomerismo
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