- Design, Synthesis, and Pesticidal Activities of Pyrimidin-4-amine Derivatives Bearing a 5-(Trifluoromethyl)-1,2,4-oxadiazole Moiety
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It is important to discover new pesticides with new modes of action because of the increasing evolution of pesticide resistance. In this study, a series of novel pyrimidin-4-amine derivatives containing a 5-(trifluoromethyl)-1,2,4-oxadiazole moiety were designed and synthesized. Their structures were confirmed by 1H NMR, 13C NMR, and HRMS. Bioassays indicated that the 29 compounds synthesized possessed excellent insecticidal activity against Mythimna separata, Aphis medicagini, and Tetranychus cinnabarinus and fungicidal activity against Pseudoperonospora cubensis. Among these pyrimidin-4-amine compounds, 5-chloro-N-(2-fluoro-4-(5-(trifluoromethyl)-1,2,4-oxadiazol-3-yl)benzyl)-6-(1-fluoroethyl)pyrimidin-4-amine (U7) and 5-bromo-N-(2-fluoro-4-(5-(trifluoromethyl)-1,2,4-oxadiazol-3-yl)benzyl)-6-(1-fluoroethyl) pyrimidin-4-amine(U8) had broad-spectrum insecticidal and fungicidal activity. The LC50 values were 3.57 ± 0.42, 4.22 ± 0.47, and 3.14 ± 0.73 mg/L for U7, U8, and flufenerim against M. separata, respectively. The EC50 values were 24.94 ± 2.13, 30.79 ± 2.21, and 3.18 ± 0.21 mg/L for U7, U8, and azoxystrobin against P. cubensis, respectively. The AChE enzymatic activity testing revealed that the enzyme activities of compounds U7, U8, and flufenerim are 0.215, 0.184, and 0.184 U/mg prot, respectively. The molecular docking results of compounds U7, U8, and flufenerim with the AChE model demonstrated the opposite docking mode between compound U7 or U8 and positive control flufenerim in the active site of AChE. The structure-activity relationships are also discussed. This work provided excellent pesticide for further optimization. Density functional theory analysis can potentially be used to design more active compounds.
- Cheng, Long,Liu, Xing-Hai,Wen, Yong-Hui,Wu, Ning-Jie,Xu, Tian-Ming
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p. 6968 - 6980
(2021/07/19)
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- Preparation process of isobutyryl ethyl acetate
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The invention provides an isobutyryl ethyl acetate preparation process which is characterized by comprising the following specific steps: step one, adding 125 mL of ethyl acetate and 13.6 g (80 mmol)of potassium mono-ethyl malonate into a three-neck flask, stirring and cooling to 0-5 DEG C, then sequentially adding 9.12 g (96 mmol) of anhydrous magnesium chloride and 27.8 mL (0.2 mol) of triethylamine, heating to 65 DEG C within 0.5 h, and stirring for 6 hours at the temperature of 65 DEG C; step two, cooling to 0 DEG C, dropwise adding 6 mL (57 mmol) of isobutyryl chloride within one hour, and carrying out reactions at the room temperature for 12 hours; step three, cooling to 0 DEG C, carefully adding 70 mL of 13% hydrochloric acid, keeping the temperature not higher than 20 DEG C in theprocess; step four, separating out an organic phase, extracting a water layer with toluene (40 mL*3), merging the organic phase, washing with a saturated sodium bicarbonate solution until the organicphase is neutral, and washing with 25 mL of saturated edible salt water, and carrying out reduced pressure distillation to remove the solvent; and step five, carrying out reduced pressure distillation on the crude product to obtain 5.5 g of colorless liquid. The method provided by the invention solves the problems of low productivity and low purity during production and manufacturing of isobutyryl ethyl acetate at present.
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Paragraph 0021-0027; 0036; 0037; 0042-0052
(2021/02/13)
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- General [4 + 1] Cyclization Approach to Access 2,2-Disubstituted Tetrahydrofurans Enabled by Electrophilic Bifunctional Peroxides
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A general [4 + 1] cyclization reaction of carbonyl nucleophiles with 2-iodomethylallyl peroxides, which function as unique electrophilic oxygen synthons, for the synthesis of a broad range of 2,2-disubstituted tetrahydrofurans is achieved under operationally simple conditions. The unprecedented asymmetric version of such reaction is also realized via chiral auxiliary-assisted cyclization, thus providing a distinct approach to access chiral tetrahydrofurans with high diastereoselectivities. The new method can be applied to the synthesis of core structure of posaconazole drug.
- Gao, Min,Zhao, Yukun,Zhong, Chen,Liu, Shengshu,Liu, Pengkang,Yin, Qi,Hu, Lin
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supporting information
p. 5679 - 5684
(2019/08/01)
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- Interrupted Baeyer–Villiger Rearrangement: Building A Stereoelectronic Trap for the Criegee Intermediate
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The instability of hydroxy peroxyesters, the elusive Criegee intermediates of the Baeyer–Villiger rearrangement, can be alleviated by selective deactivation of the stereoelectronic effects that promote the 1,2-alkyl shift. Stable cyclic Criegee intermediates constrained within a five-membered ring can be prepared by mild reduction of the respective hydroperoxy peroxyesters (β-hydroperoxy-β-peroxylactones) which were formed in high yields in reaction of β-ketoesters with BF3?Et2O/H2O2.
- Vil', Vera A.,dos Passos Gomes, Gabriel,Bityukov, Oleg V.,Lyssenko, Konstantin A.,Nikishin, Gennady I.,Alabugin, Igor V.,Terent'ev, Alexander O.
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supporting information
p. 3372 - 3376
(2018/02/28)
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- Five Roads That Converge at the Cyclic Peroxy-Criegee Intermediates: BF3-Catalyzed Synthesis of β-Hydroperoxy-β-peroxylactones
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We have discovered synthetic access to β-hydroperoxy-β-peroxylactones via BF3-catalyzed cyclizations of a variety of acyclic precursors, β-ketoesters and their silyl enol ethers, alkyl enol ethers, enol acetates, and cyclic acetals, with H2O2. Strikingly, independent of the choice of starting material, these reactions converge at the same β-hydroperoxy-β-peroxylactone products, i.e., the peroxy analogues of the previously elusive cyclic Criegee intermediate of the Baeyer-Villiger reaction. Computed thermodynamic parameters for the formation of the β-hydroperoxy-β-peroxylactones from silyl enol ethers, enol acetates, and cyclic acetals confirm that the β-peroxylactones indeed correspond to a deep energy minimum that connects a variety of the interconverting oxygen-rich species at this combined potential energy surface. The target β-hydroperoxy-β-peroxylactones were synthesized from β-ketoesters, and their silyl enol ethers, alkyl enol ethers, enol acetates, and cyclic acetals were obtained in 30-96% yields. These reactions proceed under mild conditions and open synthetic access to a broad selection of β-hydroperoxy-β-peroxylactones that are formed selectively even in those cases when alternative oxidation pathways can be expected. These β-peroxylactones are stable and can be useful for further synthetic transformations.
- Vil, Vera A.,Gomes, Gabriel Dos Passos,Ekimova, Maria V.,Lyssenko, Konstantin A.,Syroeshkin, Mikhail A.,Nikishin, Gennady I.,Alabugin, Igor V.,Terent'Ev, Alexander O.
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p. 13427 - 13445
(2018/11/02)
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- The synthesis of pyrroles and oxazoles based on gold α-imino carbene complexes
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Cationic gold complexes of α-oximimino carbenes have been identified to react with weak nucleophiles including enol ethers and nitriles. These findings allowed us to develop the highly efficient synthesis of pyrroles and oxazoles.
- Loy, Nicole S. Y.,Choi, Subin,Kim, Sunggak,Park, Cheol-Min
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supporting information
p. 7336 - 7339
(2016/06/14)
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- Synthesis of the 1,3,4-Oxadiazole Core through Thermolysis of Geminal Diazides
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The thermolysis of geminal diazides derived from acylacetate compounds is an efficient tool for the rapid construction of the 1,3,4-oxadiazole core. While a broad range of ethyl esters undergoes smooth transformation to the desired heterocycles that contain the ester moiety in moderate to high yields, the analogous tert-butyl esters give rise to the oxadiazoles with acyl groups, presumably through a pathway of decarboxylation followed by a new acyl transfer.
- Erhardt, Hellmuth,Mohr, Fabian,Kirsch, Stefan F.
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supporting information
p. 5629 - 5632
(2016/12/14)
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- General, Simple, and Chemoselective Catalysts for the Isomerization of Allylic Alcohols: The Importance of the Halide Ligand
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Remarkably simple IrIIIcatalysts enable the isomerization of primary and sec-allylic alcohols under very mild reaction conditions. X-ray absorption spectroscopy (XAS) and mass spectrometry (MS) studies indicate that the catalysts, with the general formula [Cp*IrIII], require a halide ligand for catalytic activity, but no additives or additional ligands are needed.
- Erbing, Elis,Vázquez-Romero, Ana,Bermejo Gómez, Antonio,Platero-Prats, Ana E.,Carson, Fabian,Zou, Xiaodong,Tolstoy, P?ivi,Martín-Matute, Belén
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supporting information
p. 15659 - 15663
(2016/10/25)
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- Enantioselective Mannich reaction of β-keto esters with aromatic and aliphatic imines using a cooperatively assisted bifunctional catalyst
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An efficient urea-enhanced thiourea catalyst enables the enantioselective Mannich reaction between β-keto esters and N-Boc-protected imines under mild conditions and minimal catalyst loading (1-3 mol %). Aliphatic and aromatic substituents are tolerated on both reaction partners, affording the products in good enantiomeric purity. The corresponding β-amino ketones can readily be accessed via decarboxylation without loss of enantiomeric purity.
- Neuvonen, Antti J.,Pihko, Petri M.
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supporting information
p. 5152 - 5155
(2015/01/08)
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- Tert-BuOK-Catalyzed condensation of ethyl diazoacetate to aldehydes and palladium-catalyzed 1,2-hydrogen migration for the synthesis of β-ketoesters under solvent-free conditions
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A mild and convenient method for the condensation of ethyl diazoacetate (EDA) with aldehydes catalyzed by tert-BuOK under solvent-free conditions was developed. The corresponding α-diazo-β-hydroxy esters were further converted into β-ketoesters through palladium-catalyzed 1,2-hydrogen migration under neat conditions. The two-step transformation exemplifies a simple method for the efficient and green synthesis of β-ketoesters. The Royal Society of Chemistry 2013.
- Chen, Shufeng,Yuan, Fang,Zhao, Haiying,Li, Baoguo
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p. 12616 - 12620
(2013/08/23)
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- Novel isoxazole carboxamides as growth hormone secretagogue receptor (GHS-R) antagonists
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Novel isoxazole carboxamides have been identified as growth hormone secretagogue receptor (GHS-R) antagonists. Substituent modification off the 5-position of the isoxazole ring led to analogues with potent binding affinity and functional antagonism of GHS-R. A potent analogue (32) with high aqueous solubility and good GPCR selectivity was also identified as a potential pharmacological tool for in vivo studies.
- Liu, Bo,Liu, Gang,Xin, Zhili,Serby, Micheal D.,Zhao, Hongyu,Schaefer, Verlyn G.,Falls, H. Douglas,Kaszubska, Wiweka,Collins, Christine A.,Sham, Hing L.
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p. 5223 - 5226
(2007/10/03)
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- PYRROLOPYRIDAZINE DERIVATIVES
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The invention relates to compound of the formula (I) or its salt, in which R1, R2, R3 and R4 are as defined in the description, their use of as medicament, the process for their preparation and use for the treatment of PDE-IV or TNF-α mediated diseases.
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- Microwave-assisted solution-phase synthesis of 1,4,5-trisubstituted pyrazoles
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A small parallel library of 1,4,5-trisubstituted pyrazoles was prepared in solution using a three-step procedure starting from Meldrum acid. The Meldrum acid was acylated with different acyl chlorides and the products opened with different alcohols and amines to give substituted β-keto esters and β-keto amines. Further reaction with N,N-dimethylformamide dimethylacetal and the final cyclisation were effectively carried out under microwave irradiation. Scavenger resins were employed exclusively in the first step, whereas use of microwaves allowed complete conversion of the starting materials in the other two steps. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Giacomelli, Giampaolo,Porcheddu, Andrea,Salaris, Margherita,Taddei, Maurizio
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p. 537 - 541
(2007/10/03)
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- A general synthesis of dioxolenone prodrug moieties
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A general method for the synthesis of dioxolenone prodrug moieties from appropriately substituted β-ketoesters is described. This novel and versatile sequence allows for the synthesis of alkyl- or aryl-substituted dioxolenone alcohols 8 or bromides 9. Coupling of the bromides 9 to prepare bis-dioxolenone phosphonate prodrug esters is also presented.
- Sun, Chong-Qing,Cheng, Peter T.W.,Stevenson, Jay,Dejneka, Tamara,Brown, Baerbel,Wang, Tammy C.,Robl, Jeffrey A.,Poss, Michael A.
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p. 1161 - 1164
(2007/10/03)
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- Discovery of a series of pyrrolidine-based endothelin receptor antagonists with enhanced ET(A) receptor selectivity
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Endothelins, ET-1, ET-2, and ET-3 are potent vasoconstricting and mitogenic 21-amino acid bicyclic peptides, which exert their effects upon binding to the ET(A) and ET(B) receptors. The ET(A) receptor mediates vasoconstriction and smooth muscle cell proliferation, and the ET(B) receptor mediates different effects in different tissues, including nitric oxide release from endothelial cells, and vasoconstriction in certain vascular cell types. Selective antagonists of endothelin receptor subtypes may prove useful in determining the role of endothelin in various tissue types and disease states, and hence as therapeutic agents for such diseases. The pyrrolidine carboxylic acid A-127722 has been disclosed as a potent and ET(A)-selective antagonist, and is currently undergoing clinical trials. In our efforts to find antagonists with altered selectivity (ET(A)-selective, ET(B)-selective, or nonselective), we investigated the SAR of the 2-substituent on the pyrrolidine. Compounds with alkyl groups at the 2-position possessed ET(A) selectivity improved over A-127722 (1400-fold selective), with the best of these compounds showing nearly 19,000-fold selectivity. Copyright (C) 1999 Elsevier Science Ltd.
- Boyd, Steven A.,Mantei, Robert A.,Tasker, Andrew S.,Liu, Gang,Sorensen, Bryan K.,Henry Jr., Kenneth J.,Von Geldern, Thomas W.,Winn, Martin,Wu-Wong, Jinshyun R.,Chiou, William J.,Dixon, Douglas B.,Hutchins, Charles W.,Marsh, Kennan C.,Nguyen, Bach,Opgenorth, Terry J.
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p. 991 - 1002
(2007/10/03)
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- ARYL PYRIMIDINE DERIVATIVES
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The disclosed pyrimidine derivatives, and pharmaceutically acceptable salts and N-oxides thereof, exhibit useful pharmacological properties, in particular use as selective 5HT 2B-antagonists. The invention is also directed to formulations and methods for treatment.
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- ARYL PYRIMIDINE DERIVATIVES
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The aryl pyrimidine derivatives and pharmaceutically acceptable salts and N-oxides thereof, exhibit useful pharmacological properties, including utility as selective 5HT 2B-antagonists.
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- Identification of host-related volatiles attractive to pineapple beetle Carpophilus humeralis
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Volatiles collected from oranges fed upon by Carpophilus humeralis of either sex were consistently more attractive than volatiles from beetle-free oranges in wind-tunnel bioassays. Three compounds were identified as attractants from this system: 4-ethyl-2-methoxyphenol (1), 2,5- diisopropylpyrazine (2) (a new natural product), and 2-phenylethanol (3). Identifications were confirmed with synthetic compounds that had matching chromatographic and spectral properties. Compounds 1, 2, and 3 had only slight activity alone, but were highly synergistic with each other and with propyl acetate (PA), a fruity ester that is mildly attractive to Carpophilus beetles. Compound 2 was the most active in the wind tunnel; its threshold dose was 0.5 ng when PA was present. The structural specificity for these compounds was high. Twelve phenol analogs of 1 were tested, but only one of these, 2-methoxyphenol, was more attractive than the control. Similarly, the analogs of 2, 2-isopropylpyrazine and 2,6-diisopropylpyrazine, were completely inactive. In the field, a combination of 1, 2, and 3 was not attractive by itself, but it strongly synergized attraction to fermentation volatiles, Carpophilus pheromones, or both. Compounds 1, 2, and 3 apparently have a microbial origin because all three were detected when the host fruit was pineapples instead of oranges, because they could occur in the absence of beetles, and because autoclaved pineapple began to produce the compounds after inoculation from an attractive piece of fruit. The study demonstrated that host location for this generalist species can be far more complex than responding simply to the bouquet of low-molecular-weight volatiles normally associated with fermentation.
- Zilkowski, Bruce W.,Bartelt, Robert J.,Blumberg, Daniel,James, David G.,Weaver, David K.
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p. 229 - 252
(2007/10/03)
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- The Reformatsky Reaction of 1-Acyl-3,5-dimethylpyrazoles. A Convenient Preparation of 4-Amino-3-oxoalkanoic Acid Derivatives
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The conversion of N-acylpyrazoles into β-keto esters was accomplished efficiently by the treatment with α-bromo esters and zinc dust.Using this Reformatsky reaction of N-acylpyrazoles, 4-(protected amino)-3-oxoalkanoic acid derivatives were conveniently prepared as the key intermediates in the synthesis of statines.
- Kashima, Choji,Kita, Isanobu,Takahashi, Katsumi,Hosomi, Akira
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p. 723 - 726
(2007/10/02)
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- Synthesis of the dolabellane diterpene hydrocarbon (±)-δ-araneosene
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The racemic form of the bicyclic diterpene hydrocarbon δ-araneosene (4), endowed with the dolabellane skeleton, was prepared from geraniol in two different ways. The more efficient route involved 13 steps and proceeded with an overall yield of 3.6% (average: 77% per step). With this reference sample at hand, the hitherto elusive metabolite (-)-4, a likely biogenetic precursor of cycloaraneosene ((-)-3) and sordaricin ((-)-1), could finally be isolated in ≥ 99.5% purity from the neutral fractions of the mold Sordaria araneosa CAIN (Ascomycetes).
- Jenny,Borschberg
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p. 715 - 731
(2007/10/02)
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- Structure-Activity Relations. Part 12. Antibacterial Activity of a Series of 2,4-Diamino-6-substituted 5-(4-pyridylmethylamino)pyrimidines and 2,4-Diamino-5-(4-substituted benzylamino)pyrimidines.
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A series of 6-substituted 2,4-diamino-5-(4-pyridylamino)pyrimidines and of 2,4-diamino-5-(4-substituted benzylamino)pyrimidines has been prepared.Their antibacterial activity towards L. casei, S. aureus and E. coli has been investigated.These activities have been successfully correlated by Hansch-type relations.Dependence on both lipophilicity and electronic (polar) factors has been found.The results are related to the structure and interactions with the receptor.
- Bowden, Keith,Bright, Andrew C.
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p. 514 - 539
(2007/10/02)
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- FACILE SYNTHESIS OF β-KETOESTERS BY A COUPLING REACTION OF THE REFORMATSKY REAGENT WITH ACYL CHLORIDES CATALYZED BY A PALLADIUM COMPLEX
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β-Ketoesters were obtained in good yields by the reaction of the Reformatsky reagent with acyl chlorides catalyzed by a palladium complex under mild conditions.
- Sato, Toshio,Itoh, Toshiyuki,Fujisawa, Tamotsu
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p. 1559 - 1560
(2007/10/02)
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- 1,4-Dithiinoxides
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1,4-Dithiinoxides which may be substituted with various radicals, compositions containing said products and methods useful in the treatment of ulcers are disclosed. The products are prepared by oxidation of the correspondingly substituted dithiin.
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- Aliphatic β-keto esters
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A process for the production of aliphatic β-keto esters by reacting a dialkyl ketone with a dialkylcarbonate in the presence of an at least equivalent quantity of a basic condensation agent based on the dialkyl ketone at a reaction temperature of 20° to 80° C and the reaction product is subsequently converted by acidification into the β-keto ester. By carrying out the condensation reaction in the presence of hexamethylphosphoric acid triamide as solvent advantageously higher yields of 20 to 50 % can be obtained by the inventive process of compared to conventional processes.
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- 1,4-Dihydropyridine esters
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A new class of 1,4-dihydropyridines which are characterized by the presence of ester substitutes at positions 3 and 5 of the nucleus and by the presence of an alkoxyalkyl at position 2. The products exhibit coronary activity and have particular application as coronary dilators, antifibrillators, anti-hypertensives, and as muscular and vascular spasmolytics.
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- 1,4-Dihydropyridine carboxylic acid esters useful as coronary vessel dilators and anti-hypertensives
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Certain 1,4-dihydropyridine carboxylic acid esters or their pharmaceutically acceptable non toxic salts are useful as coronary vessel dilators and antihypertensives.
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