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Zhao-xu Wang - One of the best experts on this subject based on the ideXlab platform.
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synthesis and fungicidal activity of novel 2 aryl 3 1 3 4 thiadiazolyl 6 8 methyl 1 3 benzoxazines
Bioorganic & Medicinal Chemistry Letters, 2015Co-Authors: Zilong Tang, Shuhong Chang, Zhao-xu WangAbstract:Abstract A class of novel 2-aryl-3-(1,3,4-thiadiazolyl)-6(8)-methyl-1,3-benzoxazines was prepared by reactions of 2-methyl-6-((1,3,4-thiadiazolylamino)methyl)phenols or 4-methyl-2-((1,3,4-thiadiazolylamino)methyl)phenols and 2- or 4-Nitrobenzaldehyde in the presence of TMSCl in refluxing toluene. The electron-donating methyl group on the benzene ring played an essential role on the reactivity of the substituted phenols, which was proved by DFT calculation. The fungicidal activity of the resultant products were also preliminarily evaluated, most of which displayed moderate to good fungicidal activity. Especially, compound 6f showed 98.0% activity against Sclerotonia sclerotiorum and Botrytis cinerea at concentration of 25 μg/mL.
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synthesis and fungicidal activity of novel 2 aryl 3 1 3 4 thiadiazolyl 6 8 methyl 1 3 benzoxazines
Bioorganic & Medicinal Chemistry Letters, 2015Co-Authors: Zilong Tang, Shuhong Chang, Zhao-xu WangAbstract:Abstract A class of novel 2-aryl-3-(1,3,4-thiadiazolyl)-6(8)-methyl-1,3-benzoxazines was prepared by reactions of 2-methyl-6-((1,3,4-thiadiazolylamino)methyl)phenols or 4-methyl-2-((1,3,4-thiadiazolylamino)methyl)phenols and 2- or 4-Nitrobenzaldehyde in the presence of TMSCl in refluxing toluene. The electron-donating methyl group on the benzene ring played an essential role on the reactivity of the substituted phenols, which was proved by DFT calculation. The fungicidal activity of the resultant products were also preliminarily evaluated, most of which displayed moderate to good fungicidal activity. Especially, compound 6f showed 98.0% activity against Sclerotonia sclerotiorum and Botrytis cinerea at concentration of 25 μg/mL.
Zilong Tang - One of the best experts on this subject based on the ideXlab platform.
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synthesis and fungicidal activity of novel 2 aryl 3 1 3 4 thiadiazolyl 6 8 methyl 1 3 benzoxazines
Bioorganic & Medicinal Chemistry Letters, 2015Co-Authors: Zilong Tang, Shuhong Chang, Zhao-xu WangAbstract:Abstract A class of novel 2-aryl-3-(1,3,4-thiadiazolyl)-6(8)-methyl-1,3-benzoxazines was prepared by reactions of 2-methyl-6-((1,3,4-thiadiazolylamino)methyl)phenols or 4-methyl-2-((1,3,4-thiadiazolylamino)methyl)phenols and 2- or 4-Nitrobenzaldehyde in the presence of TMSCl in refluxing toluene. The electron-donating methyl group on the benzene ring played an essential role on the reactivity of the substituted phenols, which was proved by DFT calculation. The fungicidal activity of the resultant products were also preliminarily evaluated, most of which displayed moderate to good fungicidal activity. Especially, compound 6f showed 98.0% activity against Sclerotonia sclerotiorum and Botrytis cinerea at concentration of 25 μg/mL.
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synthesis and fungicidal activity of novel 2 aryl 3 1 3 4 thiadiazolyl 6 8 methyl 1 3 benzoxazines
Bioorganic & Medicinal Chemistry Letters, 2015Co-Authors: Zilong Tang, Shuhong Chang, Zhao-xu WangAbstract:Abstract A class of novel 2-aryl-3-(1,3,4-thiadiazolyl)-6(8)-methyl-1,3-benzoxazines was prepared by reactions of 2-methyl-6-((1,3,4-thiadiazolylamino)methyl)phenols or 4-methyl-2-((1,3,4-thiadiazolylamino)methyl)phenols and 2- or 4-Nitrobenzaldehyde in the presence of TMSCl in refluxing toluene. The electron-donating methyl group on the benzene ring played an essential role on the reactivity of the substituted phenols, which was proved by DFT calculation. The fungicidal activity of the resultant products were also preliminarily evaluated, most of which displayed moderate to good fungicidal activity. Especially, compound 6f showed 98.0% activity against Sclerotonia sclerotiorum and Botrytis cinerea at concentration of 25 μg/mL.
Shuhong Chang - One of the best experts on this subject based on the ideXlab platform.
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synthesis and fungicidal activity of novel 2 aryl 3 1 3 4 thiadiazolyl 6 8 methyl 1 3 benzoxazines
Bioorganic & Medicinal Chemistry Letters, 2015Co-Authors: Zilong Tang, Shuhong Chang, Zhao-xu WangAbstract:Abstract A class of novel 2-aryl-3-(1,3,4-thiadiazolyl)-6(8)-methyl-1,3-benzoxazines was prepared by reactions of 2-methyl-6-((1,3,4-thiadiazolylamino)methyl)phenols or 4-methyl-2-((1,3,4-thiadiazolylamino)methyl)phenols and 2- or 4-Nitrobenzaldehyde in the presence of TMSCl in refluxing toluene. The electron-donating methyl group on the benzene ring played an essential role on the reactivity of the substituted phenols, which was proved by DFT calculation. The fungicidal activity of the resultant products were also preliminarily evaluated, most of which displayed moderate to good fungicidal activity. Especially, compound 6f showed 98.0% activity against Sclerotonia sclerotiorum and Botrytis cinerea at concentration of 25 μg/mL.
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synthesis and fungicidal activity of novel 2 aryl 3 1 3 4 thiadiazolyl 6 8 methyl 1 3 benzoxazines
Bioorganic & Medicinal Chemistry Letters, 2015Co-Authors: Zilong Tang, Shuhong Chang, Zhao-xu WangAbstract:Abstract A class of novel 2-aryl-3-(1,3,4-thiadiazolyl)-6(8)-methyl-1,3-benzoxazines was prepared by reactions of 2-methyl-6-((1,3,4-thiadiazolylamino)methyl)phenols or 4-methyl-2-((1,3,4-thiadiazolylamino)methyl)phenols and 2- or 4-Nitrobenzaldehyde in the presence of TMSCl in refluxing toluene. The electron-donating methyl group on the benzene ring played an essential role on the reactivity of the substituted phenols, which was proved by DFT calculation. The fungicidal activity of the resultant products were also preliminarily evaluated, most of which displayed moderate to good fungicidal activity. Especially, compound 6f showed 98.0% activity against Sclerotonia sclerotiorum and Botrytis cinerea at concentration of 25 μg/mL.
Luigi Vaccaro - One of the best experts on this subject based on the ideXlab platform.
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synthesis of zirconium phosphonate supported l proline as an effective organocatalyst for direct asymmetric aldol addition
European Journal of Organic Chemistry, 2014Co-Authors: Marco Angeloni, Oriana Piermatti, Ferdinando Pizzo, Luigi VaccaroAbstract:Stable L-proline-functionalized zirconium methyl- and/or phenylphosphonates have been prepared as amorphous solids by the precipitation of (4R)-4-[(4′-phosphonobenzyl)oxy]-L-proline and methyl- and/or phenylphosphonic acid with ZrOCl2. The supported L-proline catalysts were tested in the direct asymmetric aldol addition between several ketones and p-substituted benzaldehydes. High yields, diastereoselectivities (anti/syn up to 92:8) and enantiomeric excesses (up to 99 % ee) have been achieved. Moreover, an easy protocol for the efficient recovery of the catalytic system by simple centrifugation has been defined, and the effective reuse of the catalyst has been reported in the representative aldol addition of cyclohexanone with p-nitrobenzaldehyde. This study has shown that these L-proline immobilized catalytic systems can be used at least six times without loss of activity and with reproducible anti/syn and ee values.
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supported l proline on zirconium phosphates methyl and or phenyl phosphonates as heterogeneous organocatalysts for direct asymmetric aldol addition
Journal of Catalysis, 2011Co-Authors: Salvatore Calogero, Daniela Lanari, Mara Orrù, Oriana Piermatti, Ferdinando Pizzo, Luigi VaccaroAbstract:Zirconium phosphates methyl and/or phenyl phosphonates-supported l-proline have been prepared as amorphous solids by precipitation of (4R)-4-(phosphonooxy)-l-proline, methyl and/or phenyl phosphonic acid with ZrOCl2. The supported l-proline catalysts were tested on the direct asymmetric aldol addition of cyclohexanone to p-nitrobenzaldehyde in DMF/H2O (9:1) and in sole water. The hydrophobic groups on solid surface favor reagents’ diffusion toward proline chiral moiety increasing the catalytic activity of supported l-proline. High diastereoselectivity (anti/syn up to 94:6) and high enantiomeric excess up to 97% have been obtained.
Seung Soon Jang - One of the best experts on this subject based on the ideXlab platform.
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molecular dynamics simulations of aldol condensation catalyzed by alkylamine functionalized crystalline silica surfaces
Journal of the American Chemical Society, 2016Co-Authors: Eric G Moschetta, Christopher W Jones, Seung Soon JangAbstract:Molecular dynamics simulations are performed to investigate the cooperatively catalyzed aldol condensation between acetone and 4-Nitrobenzaldehyde on alkylamine (or alkylenamine)-grafted silica surfaces, focusing on the mechanism of the catalytic activation of the acetone and 4-Nitrobenzaldehyde by the acidic surface silanols followed by the nucleophilic attack of the basic amine functional group toward the activated reactant. From the analysis of the correlations between the catalytically active acid–base sites and reactants, it is concluded that the catalytic cooperativity of the acid–base pair can be affected by two factors: (1) the competition between the silanol and the amine (or enamine) to form a hydrogen bond with a reactant and (2) the flexibility of the alkylamine (or alkylenamine) backbone. Increasing the flexibility of the alkylamine facilitates the nucleophilic attack of the amine on the reactants. From the molecular dynamics simulations, it is found that C3 propylamine and C4 butylamine link...
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Molecular Dynamics Simulations of Aldol Condensation Catalyzed by Alkylamine-Functionalized Crystalline Silica Surfaces
2016Co-Authors: Ki Chul Kim, Eric G Moschetta, Christopher W Jones, Seung Soon JangAbstract:Molecular dynamics simulations are performed to investigate the cooperatively catalyzed aldol condensation between acetone and 4-Nitrobenzaldehyde on alkylamine (or alkylenamine)-grafted silica surfaces, focusing on the mechanism of the catalytic activation of the acetone and 4-Nitrobenzaldehyde by the acidic surface silanols followed by the nucleophilic attack of the basic amine functional group toward the activated reactant. From the analysis of the correlations between the catalytically active acid–base sites and reactants, it is concluded that the catalytic cooperativity of the acid–base pair can be affected by two factors: (1) the competition between the silanol and the amine (or enamine) to form a hydrogen bond with a reactant and (2) the flexibility of the alkylamine (or alkylenamine) backbone. Increasing the flexibility of the alkylamine facilitates the nucleophilic attack of the amine on the reactants. From the molecular dynamics simulations, it is found that C3 propylamine and C4 butylamine linkers exhibit the highest probability of reaction, which is consistent with the experimental observation that the activity of the aldol reaction on mesoporous silica depends on the length of alkylamine grafted on the silica surface. This simulation work serves as a pioneering study demonstrating how the molecular simulation approach can be successfully employed to investigate the cooperative catalytic activity of such bifunctional acid–base catalysts
