- Synthesis of diethyl 5-Ethyl-2,3-Pyridinedicarboxylate
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Diethyl 5-ethyl-2,3-pyridinedicarboxylate was synthesized using ammonium acetate as the nitrogen source. The optimum process conditions were obtained by exploring the reaction mechanism and researching the effects of reactant ratio, reaction temperature and solvent amount on the yield from all sides. Diethyl 5-ethyl-2,3-pyridinedicarboxylate yield was 98 % analysis by HPLC and the overall yield 96.8 % calculated by 2-chloro-3-oxo-succinic acid diethyl ester. The optimum process has the advantages of available initial material, simple waste-water treatment and environmental friendliness which are more applicable for industrial production.
- Cheng, Chunsheng,Ma, Xiaohua,Wei, Zhenyun
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- Preparation method of 5-alkyl substituted pyridine-2,3-diformate diester compound
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The invention provides a preparation method of a 5-alkyl substituted pyridine-2,3-diformate diester compound. Pyridine dicarboxylic acid, alcohol, an acid catalyst and a solvent are added into a reactor and heated to carry out reactions; water diversion is performed through rectification, wherein the addition amount of alcohol is 4-10 times of that of pyridine dicarboxylic acid (mole number), andthe addition amount of acid is 1-6 times of that of pyridine dicarboxylic acid (proton mole number). The preparation method is simple in process flow, high in product content and high in yield. Moreover, by controlling the process conditions, no byproduct is generated basically, the raw materials can be recycled repeatedly, and the three-waste pollution is small.
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Paragraph 0043-0057; 0061-0063; 0067-0078
(2020/07/12)
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- Preparation method for imidazolinone compound
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The invention provides a preparation method for an imidazolinone compound, belongs to the technical field of organic synthesis, and can solve the problems that a large amount of wastewater is producedand the content of impurities in the product is high in the existing process for preparing the imidazolinone compound. According to the preparation method for the imidazolinone compound provided by the invention, a solution of 5-alkyl pyridine-2,3-phthalate is synthesized from ammonium carbonate; the steps of adding water, extracting, refining and the like are avoided in post-treatment; the obtained solution of the 5-alkyl pyridine-2,3-phthalate is used for subsequent reaction; and the wastewater is not produced. Then, a catalyst is added in the process of preparing 5-alkyl pyridine-2,3-dimethylbenzene anhydride, and the pH is controlled in the subsequent reaction process, so that the production of the impurities can be avoided, and the product purity is improved. The imidazolinone compound prepared by the method provided by the invention can be used as a high-efficiency herbicide.
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Paragraph 0035-0037
(2019/03/29)
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- Process for preparing pyridine and quinoline derivatives
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The present invention pertains to a method of preparing substituted and unsubstituted N-hydroxy-2-aminobutane diacid derivatives which can be dehydrated to 2-aminobut-2-ene dioic acid derivatives, which can be subsequently converted to pyridine and quinoline derivatives.
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- Process for preparing pyridinecarboxylic acid derivatives
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The present invention pertains to a method of preparing substituted and unsubstituted N-hydroxy-2-aminobutane diacid derivatives. The invention also pertains to the use of N-hydroxy-2-aminoethane derivatives (including the N-hydroxy-2-aminobutane diacid derivatives) in the preparation of pyridine derivatives.
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- Process for the preparation of substituted and unsubstituted-2,3-pyridinedicarboxylates from chloromaleate or chlorofumurate or mixtures thereof
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There is provided a process for the preparation of dialkyl pyridinedicarboxylate compounds and derivatives thereof by reacting a dialkyl chloromaleate or chlorofumarate or a mixture thereof with an ammonium salt optionally in the presence of ammonia and an appropriately substituted α,β-unsaturated aldehyde or ketone.
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- Process for the purification of 2,3-pyridine and quinolinedicarboxylic acid diester compounds
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The present invention provides a process for the purification of 2,3-pyridine and quinolinedicarboxylic acid diester compounds via extraction with a mineral acid.
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- (2-imidazolin-2-yl) fused heteropyridine compounds, intermediates for the preparation of and use of said compounds as herbicidal agents
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There are provided novel (2-imidazolin-2-yl) fused heteropyridine compounds, and intermediate compounds for the preparation thereof, and a method for controlling a wide variety of annual and perennial plant species therewith.
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- Process for the preparation of dialkyl pyridine -2,3-dicarboxylates and derivatives thereof from dialkyl dichloromaleate
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There is provided a process for the preparation of substituted and unsubstituted-2,3-pyridinedicarboxylate compounds by reacting a dialkyl dichloromaleate with a dialkylamine to form an enamine intermediate and reacting said intermediate with an appropriately substituted α,β-unsaturated aldehyde or ketone and an ammonia source, as shown in Flow Diagam I:
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- Process for the preparation of dialkyl 2,3-pyridinedicarboxylate and derivatives thereof from an α,β-unsaturated oxime and an aminobutenedioate
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There is provided a convenient process for the preparation of commercially useful pyridinedicarboxylate compounds by the condensation of an α, β-unsaturated oxime and an aminomaleate or aminofumarate or mixtures thereof.
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- Process for the preparation of dialkyl pyridine-2,3-dicarboxylate and derivatives thereof from dialkyl dichlorosuccinate
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There is provided a process for the preparation of substituted and unsubstituted-2,3-pyridinedicarboxylate compounds by reacting a dialkyl dichlorosuccinate with a dehydrohalogenating agent, an ammonia source and an appropriately substituted α,β-unsaturated aldehyde or ketone.
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- Process for preparing pyridine-2,3-dicarboxylic acid compounds
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A process for preparing pyridine-2,3-dicarboxylic acid compounds of the following formula, which comprises preparing α-halo-oxalacetic acid diesters by reacting oxalacetic acid diester alkali metallic salts with an acid and a halogenating agent or by reacting oxalic acid diesters with halo-acetic acid esters, and then reacting the obtained α-halo-oxalacetic acid diesters with 2-propenal compounds and ammonia. STR1 wherein R1 and R2 are, identical or different, a lower alkyl group, and R3 is a hydrogen atom or a lower alkyl group. The pyridine-2,3-dicarboxylic acid componds obtained by the process of the ivention are useful as an intermediate for manufacturing agricultural chemicals and pharmaceuticals.
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- Process for the preparation of substituted and unsubstituted-2,3-pyridinedicarboxylates from chloromaleate or chlorofumarate or mixtures thereof
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There is provided a process for the preparation of dialkyl pyridinedicarboxylate compounds and derivatives thereof by reacting a dialkyl chloromaleate or chlorofumarate or a mixture thereof with an ammonium salt optionally in the presence of ammonia and an appropiately substituted α,β-unsaturated aldehyde or ketone.
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- Process for the preparation of dialkyl pyridine-2,3-dicarboxylate and derivatives thereof from dialkyl dichlorosuccinate
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There is provided a process for the preparation of substituted and unsubstituted-2,3-pyridinedicarboxylate compounds by reacting a dialkyl dichlorosuccinate with a dehydrohalogenating agent, an ammonia source and an appropriately substituted α,β-unsaturated aldehyde or ketone.
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- Process for the preparation of pyridine-2,3-dicarboxylic acid esters
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The invention relates to a process for the preparation of pyridine-2,3-dicarboxylic acid esters using novel maleic acid esters as starting materials. In the process, in a first process step, 2,3-dihalomaleic acid esters are reacted with ammonia, or ammonium salts, with the exclusion of water at a temperature of at least 50° C. to form novel 2-amino-3-halomaleic acid esters, and these are subsequently reacted further in a second process step with α,β-unsaturated aldehydes, or ketones, in the presence of an acidic catalyst and acid-binding agents at a temperature of at least 50° C. with heat being supplied until the pyridine-2,3-dicarboxylic acid esters have been formed. Pyridine-2,3-dicarboxylic acid esters of this type can be used, for example, as intermediates for synthesis of herbicides based on imidazoline. The present invention also relates to novel 2-amino-3-halomaleic acid esters, which are useful for producing the final product pyridine-2,3-dicarboxylic acid esters.
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- Process for the preparation of dialkyl, pyridine-2,3-dicarboxylates and derivatives thereof from dialkyl dichloromaleate
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There is provided a process for the preparation of substituted and unsubstituted-2,3-pyridinedicarboxylate compounds by reacting a dialkyl dichloromaleate with a source of ammonia and an appropriately substituted α,β-unsaturated aldehyde or ketone.
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- Process for preparing pyridine-2,3-dicarboxylic acid compounds
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A process for preparing pyridine-2,3-dicarboxylic acid compounds of the following formula: STR1 wherein R1 and R3 are, identical or different, each a hydrogen atom or a lower alkyl group, R2 is a hydrogen atom, a lower alkyl group, or a phenyl-(lower)alkyl group which may have halogen atom or lower alkyl group on its phenyl ring, and R4 and R5 are, identical or different, each a lower alkoxy group. The compounds are useful as an intermediate for preparing agricultural chemicals and pharmaceuticals.
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- Process for preparing pyridine-2,3-dicarboxylic acid compounds
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Improved process for preparing pyridine-2,3-dicarboxylic acid compounds of the formula: STR1 wherein R1 and R3 are each H, (un)substituted alkyl, or (un)substituted phenyl; R2 is H, (un)substituted alkyl, (un)substituted phenyl, alkylthio, alkoxy, (un)substituted phenylthio, (un)substituted phenoxy, halogen, alkoxycarbonyl, aminocarbonyl which may optionally be substituted, or cyano; or both of R1 and R2 or both R2 and R3 may combined together to form a divalent alkylene; and R4 and R5 are each alkyl which are useful as an intermediate for preparing herbicidally effective compounds, which comprises reacting an enone (II) and an aminodiester (III) of the formulae: STR2
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- Process for preparing pyridine carboxylic acid esters
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A novel method is disclosed for the preparation of 2,3-pyridine-dicarboxylates by the reaction of a ketoester such as dimethyl oxalacetate with an α,β-unsaturated aldehyde or ketone such as 2-ethylacrolein and at least 1 molar equivalent of ammonium salt in suitable solvent utilizing a dehydrogenation catalyst such as palladium on carbon.
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- Preparation of substituted and disubstituted-pyridine-2,3-dicarboxylate esters
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Pyridine-2,3-dicarboxylates of Formula I STR1 are prepared by reacting an alpha halo-beta keto ester of formula II STR2 with an alpha, beta-unsaturated aldehyde or ketone of formula III STR3 in the presence of a minimum of 2 molar equivalents of ammonium salt.
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