- Simple synthetic process of 6-methoxypyridine-3-formaldehyde
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The invention relates to a synthesis process of 6-methoxypyridine-3-formaldehyde, which comprises the following steps: 1, reacting 6-bromo-3-methylpyridine with sodium methylate under the condition ofa dry protic solvent to obtain 6-methoxy-3-methylpyridine; 2, carrying out bromination reaction on the 6-methoxy-3-methylpyridine obtained in the step 1 with a bromination reagent in an aprotic solvent under the action of a catalyst to obtain 5-(dibromomethyl)-2-methoxypyridine; and 3, carrying out a hydrolysis reaction on the 5-(dibromomethyl)-2-methoxypyridine prepared in the step 2 with an alkali in a mixed solvent of an aprotic solvent and water to prepare 6-methoxypyridine-3-formaldehyde. According to the invention, 6-bromo-3-methylpyridine is used as a main raw material, and is subjected to sodium methylate substitution, bromination and alkali metal hydroxide hydrolysis, such that a target compound is obtained. The method has the advantages of simple and accessible raw materials ineach step, simple process operation and mild reaction conditions, and is suitable for industrial amplification.
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Paragraph 0033-0037; 0051-0054
(2020/03/25)
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- A highly efficient Suzuki-Miyaura methylation of pyridines leading to the drug pirfenidone and its CD3 version (SD-560)
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Efficient introduction of methyl or methyl-d3 into aromatic and heteroaromatic systems still presents a synthetic challenge. In particular, we were in search of a non-cryogenic synthesis of the 5-CD3 version of pirfenidone (4d, also known as Pirespa, Esbriet or Pirfenex), one of the two drugs approved to date for retarding idiopathic pulmonary fibrosis (IPF), a serious, rare and fatal lung disease, with a life expectancy of 3-5 years. The methyl-deuterated version of pirfenidone (4e, also known as SD-560) was designed with the objective of attenuating the rate of drug metabolism, and our goal was to find a green methylation route to avoid the environmental and economic impact of employing alkyllithium at cryogenic temperatures. The examination of several cross-coupling strategies for the introduction of methyl or methyl-d3 into methoxypyridine and pyridone systems culminated in two green and nearly quantitative Suzuki-Miyaura cross-coupling routes in the presence of RuPhos ligand: the first, using commercially available methyl boronic acid or its CD3 analog and the second, employing potassium methyl trifluoroborate or CD3BF3K, the latter obtained by a new route in 88% yield. This led, on a scale of tens of grams, to the synthesis of pirfenidone (4d) and its d3 analog, SD-560 (4e), at 99% isotopic purity.
- Falb, Eliezer,Ulanenko, Konstantin,Tor, Andrey,Gottesfeld, Ronen,Weitman, Michal,Afri, Michal,Gottlieb, Hugo,Hassner, Alfred
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supporting information
p. 5046 - 5053
(2017/11/09)
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- Method for preparing alkyl ethers and aryl ethers
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Method for preparing compounds of the formula (III) by reacting compounds of the formula (II) with a) an alcoholate or b) an alcohol R1-OH and a base in the presence of a Cu-containing catalyst and of a ligand, where X1-5 are independently of one another either carbon or nitrogen, or in each case two adjacent X1R1, with i=1?6, linked by a formal double bond together O, S, NRH or Nrl. The ligands preferably employed are acyclic and/or cyclic oligo- and polyglycols, oligo- and polyamides or oligo- and polyamine glycols of the general formula (IV) k is an integer >0 and n is an integer >1; X and Y are independently of one another O, NH or NR1.
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Page/Page column 4
(2008/06/13)
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- Palladium catalyzed cross-methylation of bromoheterocycles with intramolecularly stabilized dimethyl indium reagents
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Although the intramolecularly stabilized [(3- dimethylamino)propyl]dimethylaluminum (1a) fails to undergo palladium-catalyzed cross-coupling with bromopyridines and with bromofuran derivatives, the analogous gallium and indium reagent lb and 1c smoothly c
- Jaber, Nimer,Schumann, Herbert,Blum, Jochanan
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p. 565 - 567
(2007/10/03)
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- Dynamics of bond breaking in ion radicals. Mechanisms and reactivity in the reductive cleavage of carbon-fluorine bonds of fluoromethylarenes
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The reductive cleavage mechanism and reactivity of the carbon-fluorine bonds in fluoromethylarenes are investigated, in liquid ammonia and in DMF, by means of cyclic voltammetry and/or redox catalysis as a function of the number of fluorine atoms and of the structure of the aryl moiety. The reduction of the trifluoro compounds, eventually leading to complete defluorination, involves the di- and monofluoro derivatives as intermediates. Carbenes do not transpire along the reaction pathway. Application of the intramolecular dissociative electron transfer model allows the quantitative rationalization, in terms of driving force and intrinsic barrier, of the variation of the cleavage reactivity of the primary anion radical with the number of fluorine atoms and of the structure of the aryl moiety as well as with the solvating properties of the medium. When, related to the structural factors thus uncovered, the primary anion radical generates the di- and monofluoro intermediates far from the electrode surface, their reduction occurs homogeneously giving rise to an apparently direct six-electron process according to an internal redox catalysis mechanism. Conversely, with rapid cleavages, the reduction of the di- and monofluoro intermediates takes place at the electrode surface and the stepwise expulsion of the fluorides ions transpire in the cyclic voltammetric patterns.
- Andrieux, Claude P.,Combellas, Catherine,Kanoufi, Fredéric,Savéant, Jean-Michel,Thiébault, André
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p. 9527 - 9540
(2007/10/03)
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- Reactions of Caesium Fluoroxysulphate with Pyridine
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Pyridine readily reacts with CsSO4F in various solvents at room temperature producing a mixture of up to three products (2-fluoropyridine, 2-pyridyl fluorosulfonate and 2-chloro or 2-alkoxypyridine), their distribution strongly depending on the solvent used.Reaction of 3-chloropyridine with CsSO4F in methanol leads regioselectively to 2-methoxy-3-chloropyridine, while 3-methylpyridine was converted into 2-methoxy-3-methyl and 2-methoxy-5-methylpyridine in a 2:1 relative ratio.
- Stavber, Stojan,Zupan, Marko
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p. 775 - 776
(2007/10/02)
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