- Chiral Vanadyl(V) Complexes Enable Efficient Asymmetric Reduction of β-Ketoamides: Application toward (S)-Duloxetine
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High-valent chiral oxidovanadium(V) complexes derived from 3,5-substituted-N-salicylidene-l-tert-leucine were used as catalysts in asymmetric reduction of N-benzyl-β-ketoamides. Among six different solvents, three different alcohol additives, and two different boranes examined, the use of pinacolborane in tetrahydrofuran (THF) with a t-BuOH additive led to the best results at -20 °C. The corresponding β-hydroxyamides can be furnished with yields up to 92percent and an enantiomeric excess (ee) up to 99percent. We have successfully extended this catalytic protocol for the synthesis of an (S)-duloxetine precursor.
- Chen, Chien-Tien,Maity, Nabin Ch.,Agarwal, Rachit,Lai, Chien-Fu,Liao, Yiya,Yu, Wei-Ru
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supporting information
p. 6408 - 6419
(2020/07/14)
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- Synthesis of Spirofurooxindoles via Phenyliodine(III) Bis(trifluoroacetate) (PIFA)-Mediated Cascade Oxidative C?O and C?C Bond Formation
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Upon treatment with solely a hypervalent iodine reagent of phenyliodine(III) bis(trifluoroacetate) (PIFA), 3-(2-hydroxyphenyl)-3-oxo-N-phenyl propanamides and a series of its derivatives were conveniently converted to a class of undocumented spirofurooxindoles under mild conditions. Control experiments provided evidence that this spirocyclization process encompassed a cascade oxidative reactions involving the formation of a C?O bond prior to that of C?C bond. (Figure presented.).
- Sun, Desong,Zhao, Xiaoyuan,Zhang, Bobo,Cong, Ying,Wan, Xintong,Bao, Mingmai,Zhao, Xue,Li, Bing,Zhang-Negrerie, Daisy,Du, Yunfei
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p. 1634 - 1638
(2018/03/21)
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- Geminal Dichlorination of Phenyliodonium Ylides of β-Dicarbonyl Compounds through Double Ligand Transfer from (Dichloroiodo)benzene
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Pre-formed phenyliodonium ylides of cyclic and acyclic β-diketones, β-keto esters and β-diesters were reacted with (dichloroiodo)benzene, resulting in transfer of both chloride ligands onto the ylidic carbon. These two hypervalent iodine(III) compounds exhibit high reactivity towards each other under mild reaction conditions and typically afford the gem-dichloride products in good yield. Upon comparison of these chlorination reactions with those of the analogous diazocarbonyl compounds, reactions of iodonium ylides were unilaterally faster, and often gave the products in higher yield.
- Tao, Jason,Tuck, Tina N.,Murphy, Graham K.
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supporting information
p. 772 - 782
(2016/03/01)
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- Synthesis of 4-Quinolones: N,O-Bis(trimethylsilyl)acetamide-Mediated Cyclization with Cleavage of Aromatic C-O Bond
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The synthesis of 1,4-dihydro-4-oxoquinoline derivatives (4-quinolones) based on a BSA [N,O-bis(trimethylsilyl)acetamide]-mediated cyclization of substituted 1-(2-methoxyphenyl)-3-(alkyl/arylamino)prop-2-en-1-ones is described. The reaction belongs to a rare set of cyclizations in which a methoxy group serves as the leaving group. Reaction takes place by the action of silylating agent under mild conditions and provides high yields of pure products following simple aqueous work-up. The versatility of the approach is exemplified by a wide range of 1-alkyl/aryl 3-carboxylates and 3-nitriles that have been prepared. A crucial advantage of this approach is the facile availability of starting methoxy compounds enabling new synthetic possibilities as well as improved cost efficiency. A new approach to the synthesis of 1,4-dihydro-4-oxoquinoline (4-quinolone) derivatives using a BSA-mediated reaction was developed; this entails an example of rare cyclizations in which an OMe group serves as a leaving group. This transformation has great synthetic potential due to the phenolic framework of starting materials and the mildness of the reagent.
- Pí?a, Ond?ej,Rádl, Stanislav
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p. 2336 - 2350
(2016/05/19)
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- Trimethylchlorosilane-Mediated Mild α-Chlorination of 1,3-Dicarbonyl Compounds Promoted by Phenyliodonium Diacetate
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Trimethylchlorosilane was used as chlorine source for the α-chlorination of 1,3-dicarbonyl compounds with phenyliodonium diacetate as oxidant at room temperature. The reaction allows the selective synthesis of α-monochlorinated products from different kinds of 1,3-dicarbonyl compounds in good yield. The potential possibility of this conversion for bromination has also been investigated.
- Chong, Siying,Su, Yingpeng,Wu, Lili,Zhang, Weigang,Ma, Junyan,Chen, Xiaowei,Huang, Danfeng,Wang, Ke-Hu,Hu, Yulai
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supporting information
p. 1359 - 1370
(2016/05/02)
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- HETEROCYCLIC COMPOUNDS FOR THE INHIBITION OF PASK
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Disclosed herein are new heterocyclic compounds and compositions and their application as pharmaceuticals for the treatment of disease. Methods of inhibiting PAS Kinase (PASK) activity in a human or animal subject are also provided for the treatment of diseases such as diabetes mellitus.
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Page/Page column 20
(2012/11/08)
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- Synthesis and biological activity of new (E)-α-(Methoxyimino) benzeneacetate derivatives containing a substituted pyrazole ring
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Strobilurins are one of the most important classes of agricultural fungicides. To discover new strobilurin analogues with high activity, a series of new strobilurin derivatives containing a substituted pyrazole in the side chain were synthesized and their biological activities were tested. The compounds were identified by 1H nuclear magnetic resonance, infrared, and elemental analysis. The test results indicated that the compounds exhibited strong fungicidal activities against Pyricularia oryzae, Phytophthora infestans, Pseudoperonospora cubenssi, and Erysiphe graminis. The relationship between structure and biological activity is discussed in terms of the effects of the substituents on the pyrazole ring. The present work demonstrates that strobilurin analogues with a 3-(substituted phenyl)-1 H-pyrazol-5-oxy side chain can be used as possible lead compounds for the development of potential agrochemicals.
- Li, Miao,Liu, Chang-Ling,Yang, J.I.-Chun,Zhang, Jin-B.O.,Li, Zhi-Nian,Zhang, Hong,Li, Zheng-Ming
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experimental part
p. 2664 - 2667
(2011/08/05)
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- INHIBITORS OF FACTOR XA WITH A NEUTRAL P1 SPECIFICITY GROUP
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The present application describes inhibitors of factor Xa with a neutral P1 specificity group of formula I: STR1 or pharmaceutically acceptable salt forms thereof, wherein R and E may be groups such as methoxy and halo.
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- Preparation of aroyl acidic esters
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Aroyl acidic esters having the formula SPC1 Wherein R1 is hydrogen, C1 -C6 alkyl, 5- or 6-membered cycloaliphatic, an aromatic radical with up to 12 C-atoms, C1 -C6 alkoxy, aroxy with up to 12 C-atoms, halogen, cyano, or methyl or ethyl substituted by fluorine and/or chlorine; and R2 is C1 -C4 alkyl, Are prepared by adding an arylmethyl ketone having the formula: SPC2 Wherein R1 is as defined above; At a temperature in the range of from 50° to 140°C to excess dialkylcarbonate having the formula: EQU1 where R2 is as defined above, CONTAINING AT LEAST THE STOICHIOMETRICALLY EQUIVALENT QUANTITY OF AN ALKALI METAL ALCOHOLATE BASED ON THE ARYLMETHYL KETONE, AND SIMULTANEOUSLY REMOVING THE ALCOHOL LIBERATED; AND CONVERTING THE ALKALI METAL SALT FORMED INTO THE AROYL ACETIC ESTER BY ADDING WATER AND AT LEAST THE STOICHIOMETRICALLY EQUIVALENT QUANTITY OF ACID.
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