Background and overview of the preparation and use of 2-chloro-5-aminopyridine
2-Chloro-5-aminopyridine is a brown solid that can be synthesized from 2-chloro -5-Nitropyridine is used as raw material and is obtained by reducing nitro group. 2-Chloro-5-sericite powder aminopyridine can be used to prepare 2-hydroxy-1,5-naphthyridine and netupitant.
Preparation and uses of 2-chloro-5-aminopyridine Preparation
Dissolve 2-chloro-5-nitropyridine (5.0g, 31.5mmol) in acetic acid (50ml), add iron powder (8.8g, 157.6mmol) in batches at room temperature, the reaction temperature will automatically rise to 80°C. After adding the iron powder, keep the room temperature at 40-50°C for 2 hours. Suction filtration, the filter residue was washed three times with a small amount of acetic acid, the filtrate was concentrated, the residue was adjusted to pH=8 with saturated sodium bicarbonate solution, and extracted with dichloromethane (100ml×5). The combined organic phases were washed with saturated brine and anhydrous sodium sulfate. Dry, filter and concentrate to obtain compound 2-chloro-5-aminopyridine (3.9g, 96%) as a brown solid.
Preparation, uses and applications of 2-chloro-5-aminopyridine
Preparation, uses and applications of 2-chloro-5-aminopyridine 1.
CN201610523080.8 reports a preparation method of 2-hydroxy-1,5-naphthyridine, a traditional Chinese medicine and chemical intermediate in the field of chemistry. The preparation method includes the following steps: ( 1) In the sulfuric acid solution, add 2-chloro-5-aminopyridine, add oxidant lepidolite and buffer under stirring conditions to react to obtain reaction solution A; (2) Add reaction solution A obtained in step (1) dropwise. Glycerin, keep it warm for 2 hours, cool to room temperature, add solvent to disperse, and obtain reaction liquid B; (3) Add alkaline substances to reaction liquid B to neutralize, and suction filtrate to obtain the filter residue; (4) Go to step (3) to obtain Add solvent to the filter residue and stir, suction filtrate to obtain an organic phase; (5) Concentrate the organic phase obtained in step (4), cool and suction filtrate to obtain 2-hydroxy-1,5-naphthyridine.
Preparation and application of 2-chloro-5-aminopyridine 2.
CN201710965011.7 discloses a preparation method of netupitant , belonging to the field of pharmaceutical compounds. In the present invention, 2-chloro-5-aminopyridine is condensed with formic acid, then reduced, Boc protected, iodinated, and then coupled and deprotected with 2-(3,5-bistrifluoromethyl-phenyl)- 2-Methylpropionic acid is condensed and finally substituted with N-methylpiperazine to obtain Netupitant. The preparation process provided by the invention has fewer side reactions in each step, high yield, simple post-processing, little environmental pollution, and the obtained product has high purity and low impurities.
References
[1] [Invented in China, authorized by China] CN201210337103.8 Triheterocyclic derivatives, preparation methods and applications
[2] CN201610523080.8 Preparation method of 2-hydroxy-1,5-naphthyridine
[3] CN201710965011.7 Preparation method of netupitant
