- Insight into the Mechanism of the Acylation of Alcohols with Acid Anhydrides Catalyzed by Phosphoric Acid Derivatives
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Insight into the mechanism of a safe, simple, and inexpensive phosphoric acid (H3PO4)-catalyzed acylation of alcohols with acid anhydrides is described. The corresponding in situ-generated diacylated mixed anhydrides, unlike traditionally proposed monoacylated mixed anhydrides, are proposed as the active species. In particular, the diacylated mixed anhydrides act as efficient catalytic acyl transfer reagents rather than as Br?nsted acid catalysts simply activating acid anhydrides. Remarkably, highly efficient phosphoric acid (1-3 mol %)-catalyzed acylation of alcohols with acid anhydrides was achieved and a 23 g scale synthesis of an ester was demonstrated. Also, phosphoric acid catalyst was effective for synthetically useful esterification from carboxylic acids, alcohols, and acid anhydride. Moreover, with regard to recent developments in chiral 1,1′-bi-2-naphthol (BINOL)-derived phosphoric acid diester catalysts toward asymmetric kinetic resolution of alcohols by acylation, some phosphate diesters were examined. As a result, a 31P NMR study and a kinetics study strongly supported not only the acid-base cooperative mechanism as previously proposed by other researchers but also the mixed anhydride mechanism as presently proposed by us.
- Hayashi, Hiroyuki,Yasukochi, Shotaro,Sakamoto, Tatsuhiro,Hatano, Manabu,Ishihara, Kazuaki
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p. 5197 - 5212
(2021/04/12)
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- Tropolonate salts as acyl-transfer catalysts under thermal and photochemical conditions: Reaction scope and mechanistic insights
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Acyl-transfer catalysis is a frequently used tool to promote the formation of carboxylic acid derivatives, which are important synthetic precursors and target compounds in organic synthesis. However, there have been only a few structural motifs known to efficiently catalyze the acyl-transfer reaction. Herein, we introduce a different acyl-transfer catalytic paradigm based on the tropolone framework. We show that tropolonate salts, due to their strong nucleophilicity and photochemical activity, can promote the coupling reaction between alcohols and carboxylic acid anhydrides or chlorides to give products under thermal or blue light photochemical conditions. Kinetic studies and density functional theory calculations suggest interesting mechanistic insights for reactions promoted by this acyl-transfer catalytic system.
- Mai, Binh Khanh,Koenigs, Rene M.,Nguyen, Thanh Vinh,Lyons, Demelza J.M.,Empel, Claire,Pace, Domenic P.,Dinh, An H.
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p. 12596 - 12606
(2020/11/18)
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- Application of quinidine or quinidine derivatives, botanical pesticide, quinidine derivative and preparation method of quinidine derivative
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The invention relates to an application of quinidine or quinidine derivatives, a botanical pesticide, a quinidine derivative and a preparation method of the quinidine derivative, and belongs to the technical field of botanical pesticides. In the prior art, quinidine is mainly used for treating heart-related diseases. Research shows that quinidine and 9S-acyloxyquinidine derivatives have better prevention and treatment effects on lepidoptera agricultural pests, and have obvious prevention and treatment effects on armyworms. The 9S-acyloxyquinidine derivatives provided by the invention are prepared by an esterification reaction of quinidine and R-COOH, has obvious insecticidal activity on lepidoptera agricultural pests, and has obvious prevention effect on armyworms in lepidoptera. A part ofthe 9S-acyloxyquinidine derivatives have a prevention effect on armyworms than commercial botanical insecticide toosendanin, and can be used for preparing botanical lepidoptera agricultural pest insecticides.
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Paragraph 0054-0068
(2020/02/17)
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- Synthesis of Novel (9S)-Acyloxy Derivatives of Quinidine and Dihydroquinidine as Insecticidal Agents
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Endeavor to discover biorational natural products-based insecticides, two series (30) of novel (9S)-acyloxy derivatives of quinidine and dihydroquinidine were prepared and assessed for their insecticidal activity against Mythimna separata in vivo by the leaf-dipping method at 1 mg/mL. Among all the compounds, especially four derivatives exhibited the best insecticidal activity with final mortality rates of 71.4 %, 75.0 %, 71.4 %, and 75.0 %, respectively. Relatively speaking, 9-hydroxy group is well tolerated, and the results showed that after modification of the hydroxy group with an acyloxy group, the insecticidal activity was significantly increased; the configuration at C8/9 position is important for insecticidal activity, and the (9S)-configuration is optimal; modification of the out-ring double bond is acceptable, and hydrogenation of the double bond enhances insecticidal activity. These preliminary results will pave the way for further modification of quinidine in the development of potential new insecticides.
- Che, Zhiping,Yang, Jinming,Sun, Di,Tian, Yuee,Liu, Shengming,Lin, Xiaomin,Jiang, Jia,Chen, Genqiang
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- 9R-acyloxy quinine derivatives, preparation method therefor, application of quinine or derivatives thereof and botanical insecticides
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The invention relates to 9R-acyloxy quinine derivatives, a preparation method therefor, an application of quinine or derivatives thereof and botanical insecticides and belongs to the technical field of botanical pesticides. The 9R-acyloxy quinine derivatives disclosed by the invention are prepared through subjecting the quinine and R-COOH to an esterification reaction, have remarkable insecticidalactivity to Lepidoptera agricultural insect pests and have a remarkable control efficiency to armyworms of Lepidoptera, and part of the 9R-acyloxy quinine derivatives have an armyworm control efficiency already exceeding that of a commercialized botanical insecticide, i.e., toosendanin and can be applied to preparation of botanical insecticides for the Lepidoptera agricultural insect pests. In the prior art, the quinine is mainly used for treating human diseases induced by Plasmodium falciparum; and in the invention, discovered through researches, the quinine also has a relatively good control action on the Lepidoptera agricultural insect pests and has a remarkable control efficiency to the armyworms.
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Paragraph 0051-0055; 0060-0066
(2020/02/17)
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- Origin of and a Solution for Uneven Efficiency by Cinchona Alkaloid-Derived, Pseudoenantiomeric Catalysts for Asymmetric Reactions
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Cinchona alkaloid-derived chiral catalysts represent one of the most widely applied classes of organocatalysts, which have been successfully utilized in the promotion of a wide variety of asymmetric reactions. Cinchona alkaloids exist in nature as pseudoe
- Hu, Bin,Bezpalko, Mark W.,Fei, Chao,Dickie, Diane A.,Foxman, Bruce M.,Deng, Li
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supporting information
p. 13913 - 13920
(2018/10/20)
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- Recyclable fluorous cinchona alkaloid ester as a chiral promoter for asymmetric fluorination of β-ketoesters
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A fluorous cinchona alkaloid ester has been developed as a chiral promoter for the asymmetric fluorination of β-ketoesters. It has comparable reactivity and selectivity to the nonfluorous versions of cinchona alkaloids and can be easily recovered from the
- Yi, Wen-Bin,Huang, Xin,Zhang, Zijuan,Zhu, Dian-Rong,Cai, Chun,Zhang, Wei
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experimental part
p. 1233 - 1240
(2012/09/21)
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- Organocatalytic asymmetric synthesis of quinine and quinidine
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Quinine and quinidine were synthesized by a highly enantio- and stereoselective approach starting from a proline-catalyzed asymmetric cycloaldolization of benzyl bis(2-formylethyl)carbamate which gave a 70:30 mixture of (3R,4R)-N-Cbz-3-hydroxymethyl-4-hydroxypiperidine (96% ee) and its 4S-epimer (92% ee) in 94% yield after in situ NaBH4 reduction.
- Sarkar, Shaheen M.,Taira, Yuko,Nakano, Ayako,Takahashi, Keisuske,Ishihara, Jun,Hatakeyama, Susumi
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supporting information; experimental part
p. 923 - 927
(2011/03/20)
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- Synthesis and biological activity of fatty acid derivatives of quinine
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Derivatives of quinine with fatty acids including polyunsaturated fatty acids were prepared. They showed moderate antimalarial activity as compared with quinine itself using Plasmodium falciparum. The activities were not dependent on whether the fatty acyl group was saturated or unsaturated. On the other hand, the derivatives showed significantly higher cytotoxicity against a mammary tumor cell line FM3A than quinine itself. Calculating from these data, an acetyl derivative of quinine with the shortest acyl group was found to give the highest selectivity.
- Kumura, Naokazu,Izumi, Minoru,Nakajima, Shuhei,Shimizu, Sakayu,Kim, Hye-Sook,Wataya, Yusuke,Baba, Naomichi
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p. 2250 - 2253
(2008/02/03)
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- Electrophilic fluorination mediated by cinchona alkaloids: Highly enantioselective synthesis of α-fluoro-α-phenylglycine derivatives
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A decisive step forward: A one step fluorination on modified cinchona alkaloids produced a new range of enantiopure fluorinating agents that display high enantioselectivities in electrophilic fluorination. The first enantioselective synthesis of N-protect
- Mohar, Barbara,Baudoux, Jerome,Plaquevent, Jean-Christophe,Cahard, Dominique
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p. 4214 - 4216
(2007/10/03)
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