- Preparation method of dimethyl 5-methoxymethyl-2, 3-pyridinedicarboxylate
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The invention relates to the field of pesticide synthesis, and discloses a preparation method of dimethyl 5-methoxymethyl-2, 3-pyridinedicarboxylate. The method comprises the steps of 1) in the presence of alkali, carrying out transesterification on dimethyl 5-methyl-2, 3-pyridinedicarboxylate and methanol; 2) in the presence of an organic solvent, carrying out bromination reaction on the dimethyl 5-methyl-2, 3-pyridinedicarboxylate and a brominating agent to obtain a reaction product containing the dimethyl 5-methyl-2, 3-pyridinedicarboxylate, a monobromide, a dibromide and a tribromide; 3) performing quaternary ammonium salinization on the monobromide contained in the reaction product, and separating the monobromide from the reaction product subjected to quaternary ammonium salinization to obtain quaternary ammonium salt; and (4) enabling quaternary ammonium salt to be in contact with a sodium methoxide solution so as to obtain the dimethyl 5-methoxymethyl-2, 3-pyridinedicarboxylate. According to the method disclosed by the invention, few impurities are generated in the reaction process, and the steps are simple.
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Paragraph 0097-0098; 0103-0104; 0109-0110
(2021/06/26)
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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 0042; 0043
(2019/03/29)
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- Microwave-assisted Diels-Alder reaction supported on graphite
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The coupling of graphite (as a support) with microwaves (as an energy source), a new type of "dry reaction", was studied for some Diels-Alder reactions involving anthracene and azadienes. Graphite is responsible for a high-temperature gradient leading to increased reaction rates as compared to conventional procedures using a solvent. VCH Verlagsgesellschaft mbH, 1996.
- Garrigues, Bernard,Laporte, Christian,Laurent, Regis,Laporterie, Andre,Dubac, Jacques
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p. 739 - 741
(2007/10/03)
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- Ultrasound Assisted Diels-Alder Reactions of 1-Azadienes with "Normal" Electronic Demand.
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Ultrasound irradiaton accelerates hetero Diels-Alder reactions between 1-dimethylamino-1-azadienes and electron-defficient dienophiles.Besides the lower reaction times and increased yields, other advantages of the sonicated reactions are the possibility of isolating previously unknown adducts due to the milder reaction conditions and, in some cases, the decrease in side reactions.
- Villacampa, Mercedes,Perez, Jose Maria,Avendano, Carmen,Menendez, J. Carlos
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p. 10047 - 10054
(2007/10/02)
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- Process for the preparation of pyridine-2,3-dicarboxylic acid derivatives
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A pyridine compound of formula I is prepared from a tetrahydropyridine compound of formula II in a single step or procedure under oxidising conditions. The R meanings are fully defined in the specification but preferably R1 and R3 represent hydrogen, R2, R11 and R12 represent alkyl, and R4 and R5 represent hydroxy or alkoxy or together represent -O- or -NR10- where R10 represents alkyl, cyanoalkyl, aminocarbonylalkyl or phenyl.
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