- Investigation of Masked N-Acyl-N-isocyanates: Support for Oxadiazolones as Blocked N-Isocyanate Precursors
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In contrast to carbon-substituted isocyanates that are common building blocks, N-substituted isocyanates remain underdeveloped and reports on their N-acyl derivatives (i. e. amido-isocyanates) are exceedingly rare. Herein, amido-isocyanates were investiga
- Gagné-Monfette, William,Vincent-Rocan, Jean-Fran?ois,Lutes, Owen C.,O'Keefe, Geneviève F.,Jeanneret, Alexandria D. M.,Blanger, Claire,Ivanovich, Ryan A.,Beauchemin, André M.
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supporting information
p. 14051 - 14056
(2021/09/14)
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- The invention relates to a halogen formate synthesis method of intermediate [...] physiologically pymetrozine
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The invention discloses a method for synthesizing a pymetrozine intermediate (oxadiazole ketone) by utilizing halogenated formate ester. According to the method, oxadiazole ketone is generated through a ring-closure reaction between acethydrazide and halogenated formate ester under certain conditions. Phosgene, diphosgene or triphosgene which can easily trigger group safety accidents is prevented from being utilized as a process route for the ring-closure reaction; such halogenated formate ester as phenyl chloroformate or phenyl chloroformate is utilized for replacing previously common virulent phosgene, diphosgene or triphosgene as a carbonylation ring-closure reagent; under the action of catalysts, a ring-closure cyclization reaction is performed for preparation of oxadiazole ketone; generation of virulent phosgene during a production process is avoided, so that major hidden dangers are reduced; the method has the advantages that technology is safe and reliable, reaction conditions are mild and easy to control, after-treatment is convenient, and an environmental-friendly effect is achieved.
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Paragraph 0027; 0043-0048
(2019/04/26)
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- The invention relates to a synthetic pymetrozine intermediate [...] physiologically carbonate method
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The invention discloses a method for synthesizing a pymetrozine intermediate (oxadiazole ketone) by utilizing carbonate ester. According to the method, hydrazine hydrate and an acetic acid ester are utilized as raw materials for hydrazine-ester condensation to synthesize acethydrazide; oxadiazole ketone is generated through a ring-closure reaction between acethydrazide and carbonate ester under certain conditions. Such environmental-friendly non-toxic or low-toxic dimethyl carbonate, diphenyl carbonate or dibenzyl carbonate is utilized for replacing previously common virulent phosgene, diphosgene or triphosgene as a carbonylation ring-closure reagent; under the action of catalysts, a ring-closure cyclization reaction is performed for preparation of oxadiazole ketone; virulent phosgene and a great amount of inorganic solid hazardous waste are prevented from generating during a production process, so that major hidden dangers are reduced; the method has the advantages that the process is safe and reliable, reaction conditions are mild and easy to control, after-treatment is convenient, and an environmental-friendly effect is achieved.
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Paragraph 0055; 0057
(2019/04/14)
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- A high-efficiency green pymetrozine preparation method
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The invention discloses a high-efficiency and green method for preparing pymetrozine. According to the method, a byproduct methyl acetate produced in a pymetrozine condensation step serves as a raw material and replaces ethyl acetate in a traditional process for synthesizing acethydrazide, and the produced byproduct methanol can serve as a solvent in a subsequent step, so that the byproduct is recycled, and the raw material utilization rate is improved. Hydrogen chloride or concentrated hydrochloric acid in a traditional process is replaced by adopting a saturated hydrogen chloride methanol solution in the condensation step, and moisture in the system is avoided, so that amino triazone is subjected to a hydrolysis reaction, and byproducts are basically eliminated. According to the method, the yield of the product and the utilization rate of the hydrogen chloride are improved, the reaction time is shortened, emission of wastewater and waste gas is reduced, the comprehensive production cost is reduced, and better conditions are created for industrial large-scale production of the product.
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Paragraph 0008; 0030; 0032
(2017/08/25)
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- Process for producing 2-methyl-1,3,4-oxadiazole-5(4H)-ketone
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The invention discloses a process for producing 2-methyl-1,3,4-oxadiazole-5(4H)-ketone. The 2-methyl-1,3,4-oxadiazole-5(4H)-ketone is a main chemical finished product. The process comprises the following steps: 1, adding a dichloroethane solution of acethydrazide into a 5,000-liter ring formation kettle, closing a manhole cover, stirring and reducing the temperature to 10 DEG C; 2, checking and starting a tail gas absorption system; 3, after dropwise addition is completed, performing reaction for 24h in a manner that the temperature of the ring formation kettle is controlled to be below 45 DEG C, and after reaction is completed, adding a small amount of NaHCO3 to neutralize a small amount of hydrogen chloride contained in a solution; 4, after reaction is completed, keeping introducing nitrogen for 1h, and collecting and guiding generated HCl tail gas (containing trace diphosgene which does not participate in the reaction), performing two-stage water falling film absorption and one-stage liquid caustic soda bubble absorption, and then discharging through a 25m-high exhaust funnel (No. 1 exhaust funnel); 5, adding measured water into the kettle, and standing for 2h for demixing.
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Paragraph 0001-0003
(2017/07/11)
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- Propylene oxide assisted one-pot, tandem synthesis of substituted-1,3,4- oxadiazole-2(3H)-ones in water
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It has been developed for the synthesis of substituted-1,3,4-oxadiazole- 2(3H)-one derivatives via a novel one-pot, tandem procedure assisted by propylene oxide. The 5-substitued-1,3,4-oxadiazole-2(3H)-ones and 3,5-disubstitued-1,3,4-oxadiazole-2(3H)-ones were, respectively, obtained from three-component reaction of acylhydrazines, carbon disulfide, and propylene oxide, and four-component reaction of acylhydarazines, carbon disulfide, propylene oxide, and organic halides. The reactions were carried out using water as solvent in the presence of potassium phosphate to afford the expected products in good to excellent yields.
- Yan, Xu,Zhou, Shuo,Wang, Yuanqiang,Ge, Zemei,Cheng, Tieming,Li, Runtao
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experimental part
p. 7978 - 7983
(2012/09/21)
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- Synthesis of GABAA receptor agonists and evaluation of their α-subunit selectivity and orientation in the GABA binding site
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Drugs used to treat various disorders target GABAA receptors. To develop α subunit selective compounds, we synthesized 5-(4-piperidyl)-3-isoxazolol (4-PIOL) derivatives. The 3-isoxazolol moiety was substituted by 1,3,5-oxadiazol-2-one, 1,3,5-oxadiazol-2-thione, and substituted 1,2,4-triazol-3-ol heterocycles with modifications to the basic piperidine substituent as well as substituents without basic nitrogen. Compounds were screened by [3H]muscimol binding and in patch-clamp experiments with heterologously expressed GABAA αiβ 3γ2 receptors (i = 1-6). The effects of 5-aminomethyl-3H-[1,3,4]oxadiazol-2-one 5d were comparable to GABA for all α subunit isoforms. 5-piperidin-4-yl-3H-[1,3,4]oxadiazol-2-one 5a and 5-piperidin-4-yl-3H-[1,3,4]oxadiazol-2-thione 6a were weak agonists at α2-, α3-, and α5-containing receptors. When coapplied with GABA, they were antagonistic in α2-, α4-, and α6-containing receptors and potentiated α3-containing receptors. 6a protected GABA binding site cysteine-substitution mutants α1F64C and α1S68C from reacting with methanethiosulfonate-ethylsulfonate. 6a specifically covalently modified the α1R66C thiol, in the GABA binding site, through its oxadiazolethione sulfur. These results demonstrate the feasibility of synthesizing α subtype selective GABA mimetic drugs.
- Jansen, Michaela,Rabe, Holger,Strehle, Axelle,Dieler, Sandra,Debus, Fabian,Dannhardt, Gerd,Akabas, Myles H.,Lüddens, Hartmut
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experimental part
p. 4430 - 4448
(2009/06/06)
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- Synthesis of 3,5-Disubstituted 1-Amino-1,3,5-triazine-2,4,6-triones (or 1-Aminocyanurates) by Cyclic Transformation of 1,3,4-Oxadiazol-2(3H)-one Derivatives
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The 5-aryl(or methyl)-3-phenylcarbamoyl-3,4-oxadiazol-2(3H)-ones 2, in the presence of sodium hydride in anhydrous dimethylformamide, were transformed into 1-benzamido(or acetamido)-3,5-diphenyl-1,3,5-triazine-2,4,6-trione derivatives 7 in poor yields. Ho
- Chau, Francois,Malanda, Jean-Claude,Milcent, Rene
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p. 1603 - 1606
(2007/10/03)
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- Preparation of 4-amino-1,2,4-triazol-5-ones
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A process for the preparation of 4-amino-1,2,4-triazol-5-one of the formula STR1 in which R is alkyl, comprising in a first step reacting phosgene with an acylhydrazide of the formula STR2 to produce an oxadiazolinone of the formula STR3 and in a second step reacting the oxadiazolinone with hydrazine hydrate.
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