1975-50-4Relevant articles and documents
Preparation of 2-arylindole-4-carboxylic amide derivatives
Kuethe, Jeffrey T.,Davies, Ian W.
, p. 11381 - 11390 (2006)
A practical, highly efficient protocol has been developed for the synthesis of functionalized 2-arylindole-4-carboxylic amide derivatives. Commercially available methyl 2-methyl-3-nitrobenzoate gave substituted nitrostyrene benzoic acids by reaction with aromatic aldehydes in the presence of DBU in DMSO. Conversion of these products to the desired amides was followed by Pd-catalyzed reductive cyclization employing carbon monoxide as the terminal reductant to provide the 2-arylindole-4-carboxylic amide derivatives in excellent overall yield for the simple three-step sequence.
Method for co-production 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid
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Paragraph 0022; 0025; 0028; 0033, (2020/10/14)
The invention discloses a method for co-production of 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid. The method is characterized by comprising the following steps: (1) feeding 3-nitro-o-xylene and dilute nitric acid into an oxidation reaction kettle, carrying out heating, and conducting reacting under certain pressure by using oxygen as an oxidant; (2) after the reaction is finished, discharging an oxidation reaction solution to obtain a crude product; (3) washing the crude product with water, conducting esterifying, and performing distilling to recover a solvent after the reaction is finished, thereby obtaining an esterified concentrated solution; (4) adding alkali into the esterification concentrated solution to adjust a pH value, carrying out layering, and distilling anorganic layer under reduced pressure to recover 3-nitro-2-nitrobenzoic acid; and (5) extracting a water layer with an organic solvent, adjusting an pH value with an acid, and performing filtering anddrying to obtain the 2-methyl-6-nitrobenzoic acid. In a low-concentration nitric acid environment, 3-nitro-2-nitrobenzoic acid is produced and 2-methyl-6-nitrobenzoic acid is co-produced with oxygen used as an oxidizing agent, so the problems of low selectivity of 3-nitro-o-xylene in an oxidation process and high risks in a concentrated nitric acid oxidation process are solved.
Clean production method to oxidize 3-nitro-o-xylene into 2-methyl-3-nitrobenzoic acid
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Paragraph 0024-0047, (2019/07/04)
The invention discloses a clean production method to oxidize 3-nitro-o-xylene into 2-methyl-3-nitrobenzoic acid. The clean production method comprises the steps of adding 3-nitro-o-xylene with an acidinto an organic solvent under the action of a catalyst, adding an oxidant, and stirring to allow reacting to obtain 2-methyl-3-nitrobenzoic acid, wherein the oxidant is hydrogen peroxide, and the catalyst is a transition metal compound. The hydrogen peroxide is used herein as a clean oxidant, so that the oxidants, such as potassium permanganate, causing high environmental pollution are avoided. The reaction system is mild; post-reaction treatment is simple and practical; reaction selectivity is good; few byproducts are produced; the target product is easy to purify; both the yield and purityare high; the cost is low; the clean production method has a good industrial application prospect.