Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two com...Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two competitive mechanisms in which the carbon atom of acetylene or carbon monoxide attacked and inserted from two different directions of the six-membered ring reactant to clarify the principle characteristics of this transformation.The calculation results reveal that:(i)the insertion process of alkyne or carbon monoxide is the key step of the reaction;(ii)for the(5+2)cycloaddition reaction of acetylene,higher energy is required to break the Rh−O bond of the reactant,and the reaction tends to complete the insertion from the side of the Rh−C bond;(iii)for the(5+1)cycloaddition of carbon monoxide,both reaction paths have lower activation free energy,and the two will generate a competition mechanism.展开更多
In order to have efficient and highly stereoselective cyclopropanating reagents, the cyclopropabation reaction of ethylene promoted with Samarium（Ⅱ） carbenoid [Simmons-Smith（SS）reagent] were studied by means of B...In order to have efficient and highly stereoselective cyclopropanating reagents, the cyclopropabation reaction of ethylene promoted with Samarium（Ⅱ） carbenoid [Simmons-Smith（SS）reagent] were studied by means of B3LYP hybrid density functional method. The geometries for reactants, transition states and products are completely optimized. All transition states were verified by the vibrational analysis and the intrinsic reaction coordinate （IRC） calculations. The results showed that, identical with the lithium carbenoid, CH3SmCH2X（X=Cl, Br and Ⅰ） can fairly react with ethylene via both methylene transfer pathway （pathway A） and carbometalation pathway （pathway B）. And the cyclopropanation reaction via methylene transfer pathway proceeds with a lower barrier and at lower temperatures.展开更多
The objective of this study was to systematically evaluate the efficacy and safety of Huachansu capsules in the treatment of esophageal cancer.We searched all relevant Chine se and English documents in the Cochrane Li...The objective of this study was to systematically evaluate the efficacy and safety of Huachansu capsules in the treatment of esophageal cancer.We searched all relevant Chine se and English documents in the Cochrane Libraty Clinical Controlled Trials,PubMed,EMB ASE,CNKI,and VIP databases,from the time the databases were established to December 2020.The studies were selected according to the inclusion and exclusion criteria,and their quality was evaluated.We used RevMan 5.4 to conduct the meta-analysis of measurement indicators and intervention measures.Six randomized controlled trials comprising 526 patients with esophageal cancer were included in the study.Compared with radiotherapy and chemotherapy alone,oral Huachansu capsules combined with radiotherapy and chemotherapy improved the clinical efficacy(risk ratio[RR]=1.35,95%confidence interval[CI],1.17-1.55,P<0.0001),quality of life(weighted mean difference[MD]=10.01,95%CI[3.39-16.64],P=0.003),and immune level(CD3+:MD=4.99,95%CI[3.70-6.29],P<0.0001;CD4+:MD=6.49,95%CI[5.55-7.42],P<0.0001;CD5+:MD=0.20,95%CI[0.11-0.28],P<0.0001),and reduced toxic and side effects(reductions in white blood cell count:RR=0.63,95%CI[0.44-0.90],P=0.01;Reductions in blood platelet:RR=0.70,95%CI[0.52-0.94],P=0.02;Gastrointestinal reaction:RR=0.73,95%CI[0.59-0.89],P=0.002).However,the number of included studies was small,and conclusions still need to be further verified using larger samples and high-quality randomized,double-blind controlled trials.展开更多
基金This work was supported by the Natural Science Foundation of Gansu Province(20JR5RA479)the Outstanding Youth Research Program of Lanzhou University of Arts and Sciences(2018JCQN008).
文摘Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two competitive mechanisms in which the carbon atom of acetylene or carbon monoxide attacked and inserted from two different directions of the six-membered ring reactant to clarify the principle characteristics of this transformation.The calculation results reveal that:(i)the insertion process of alkyne or carbon monoxide is the key step of the reaction;(ii)for the(5+2)cycloaddition reaction of acetylene,higher energy is required to break the Rh−O bond of the reactant,and the reaction tends to complete the insertion from the side of the Rh−C bond;(iii)for the(5+1)cycloaddition of carbon monoxide,both reaction paths have lower activation free energy,and the two will generate a competition mechanism.
基金This work was supported by the Northwest Normal University Science Foundation of Gansu Province （No. NWNU-QN-2001-08）.
文摘In order to have efficient and highly stereoselective cyclopropanating reagents, the cyclopropabation reaction of ethylene promoted with Samarium（Ⅱ） carbenoid [Simmons-Smith（SS）reagent] were studied by means of B3LYP hybrid density functional method. The geometries for reactants, transition states and products are completely optimized. All transition states were verified by the vibrational analysis and the intrinsic reaction coordinate （IRC） calculations. The results showed that, identical with the lithium carbenoid, CH3SmCH2X（X=Cl, Br and Ⅰ） can fairly react with ethylene via both methylene transfer pathway （pathway A） and carbometalation pathway （pathway B）. And the cyclopropanation reaction via methylene transfer pathway proceeds with a lower barrier and at lower temperatures.
文摘The objective of this study was to systematically evaluate the efficacy and safety of Huachansu capsules in the treatment of esophageal cancer.We searched all relevant Chine se and English documents in the Cochrane Libraty Clinical Controlled Trials,PubMed,EMB ASE,CNKI,and VIP databases,from the time the databases were established to December 2020.The studies were selected according to the inclusion and exclusion criteria,and their quality was evaluated.We used RevMan 5.4 to conduct the meta-analysis of measurement indicators and intervention measures.Six randomized controlled trials comprising 526 patients with esophageal cancer were included in the study.Compared with radiotherapy and chemotherapy alone,oral Huachansu capsules combined with radiotherapy and chemotherapy improved the clinical efficacy(risk ratio[RR]=1.35,95%confidence interval[CI],1.17-1.55,P<0.0001),quality of life(weighted mean difference[MD]=10.01,95%CI[3.39-16.64],P=0.003),and immune level(CD3+:MD=4.99,95%CI[3.70-6.29],P<0.0001;CD4+:MD=6.49,95%CI[5.55-7.42],P<0.0001;CD5+:MD=0.20,95%CI[0.11-0.28],P<0.0001),and reduced toxic and side effects(reductions in white blood cell count:RR=0.63,95%CI[0.44-0.90],P=0.01;Reductions in blood platelet:RR=0.70,95%CI[0.52-0.94],P=0.02;Gastrointestinal reaction:RR=0.73,95%CI[0.59-0.89],P=0.002).However,the number of included studies was small,and conclusions still need to be further verified using larger samples and high-quality randomized,double-blind controlled trials.
