Background and overview[1]
Anthranilic acid isopropylamide can be used as a pharmaceutical synthesis intermediate, such as the preparation of bentazone. Bentazone is an important post-emergence herbicide, its chemical name is 3-isopropyl-(1H)-benzo-2,1,3-thiadiazin-4-one-2,2-dioxide It was originally successfully developed by the German BASF company and widely used around the world. It is a selective contact-type post-emergent herbicide, used to treat the stems and leaves of weeds in the seedling stage. The drug has the characteristics of strong contact killing, good selectivity, and weed killing. It is mainly used in rice, soybeans, For crops such as peanuts and wheat, it controls broadleaf weeds and sedge weeds, but is ineffective against gramineous weeds. In the existing technology, the preparation process of bentazone technical material mostly adopts the methods of synthesizing water-washed bentazon dichloroethane solution, alkali extraction, acidification, water washing, alkali extraction, acidification, extraction and concentration. The above methods have problems such as high production costs, complex production methods, harsh production conditions, a large amount of salty wastewater pollution, serious dust pollution, and low yield and low purity of the products obtained during the production process. Using isopropylamide anthranilic acid as the starting material can solve the above problems.
Preparation[1]
Preparation of anthranilic acid isopropylamide: Dissolve isatoic anhydride in dichloroethane, add isopropylamine dropwise while raising the temperature, raise the temperature to 60°C, incubate for 0.8h, and then wash and remove with saturated sodium carbonate. The dichloroethane was removed to obtain a light yellow o-amino-N-isopropylbenzamide solution, in which the mass ratio of isatoic anhydride, dichloroethane and isopropylamine was 3.5:2.6:1.8.
Application
Anthranilic acid isopropylamide can be used as a pharmaceutical synthesis intermediate, such as preparing bentazone: α-methylpyridine and dichloroethane are added to anthranilic acid isopropylamide, and trioxide is added dropwise Sulfur generates a translucent milky white double salt. After stirring at room temperature for 0.4 to 0.8 hours, add preheated amide dichloroethane and stir until crystalline amide pyridine sulfur trioxide double salt precipitates. Add the catalyst and then add dropwise Phosphorus oxychloride solution is heated to reflux. After reacting for 2 to 3 hours, it is cooled to room temperature. After hydrolysis, alkaline washing and water washing, it is extracted with dilute alkali solution and layered to obtain bentazone sodium salt. After acidification and filtration, it is light yellow. The solid substance can be dried to obtain bentazone technical material.
Main reference materials
[1] (CN107445920) A kind of production method of Bentazone original drug
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