Preparation and application of 2,3-diaminopyridine_Industrial additives

Background and overview of preparation and application of 2,3-diaminopyridine

The molecular formula of 2,3-diaminopyridine is C7H7N3, with a molecular weight of 109.13. It is a toxic and irritating substance with a melting point of 114-116°C and a flash point of 205°C. Pyridine is a six-membered heterocyclic compound containing one nitrogen atom, that is, one carbon of the benzene molecule is replaced by nitrogen. It has many special medicinal effects and structural properties. Pyridine derivatives widely exist in nature, and many of them have special pharmacological effects.

Preparation and application of 2,3-diaminopyridine

Preparation and application report of 2,3-diaminopyridine 1.

A preparation method of 2,3-diaminopyridine, including the steps:

(1) Dissolve 2,3-dinitropyridine in methylene chloride, add palladium on carbon and stir continuously. Pour hydrogen into the reaction bottle, raise the temperature to 50°C, and heat for 1.5 hours to obtain a mixed solution. ;

(2) Filter the mixture. During the filtration process, pay attention to prevent the palladium carbon from clogging the filter pores. Extract three times, and then rotary evaporate under reduced pressure to obtain 2,3-diaminopyridine.

Preparation and application report of 2,3-diaminopyridine 2.

Add 2-chloro-3-aminopyridine (23gm); CuSO₄·5H₂O (9.2gm) and ammonia solution (25%; 230ml) to a 0.4 liter autoclave. The solution was stirred at 25-30°C and an ammonia pressure of 3kg/cm² was applied. The resulting mass was gradually heated to 130°C and maintained at this temperature for 8 hours under a pressure of 18-24 kg/cm2. After the reaction is complete, the reaction mixture is slowly cooled to ambient temperature while excess ammonia is purged, scrubbed and recycled. The product was then extracted from the reaction with ethyl acetate (190 ml) at 50-55°C. The organic layer was collected at ambient temperature and 60-70% of the added ethyl acetate was distilled off and the material was cooled to about 5-8°C. The resulting filter cake was filtered and washed with ethyl acetate. After drying the material under vacuum at 50 to 60°C for 8 hours, 11 gm of 2,3-diaminopyridine was obtained (56% yield); melting point 112 to 114°C; HPLC purity 99.5%. Set aside the ethyl acetate for recycling. The product was confirmed by mass spectrometry and 1H NMR. ms: m/e109(M+); ¹H NMR (DMSO-D6) δ7.26ppm (d, 6H, 1H), δ6.66ppm (t, 4H, 1H), δ6.36ppm ( d, 5H, 1H), δ5.32ppm (s, 2H, NH2), δ4.63ppm (s, 2H, NH2)

Preparation and application of 2,3-diaminopyridine

Carbon dots are a new type of fluorescent carbon material with a diameter of about 10nm. Its synthesis method is cheap and simple. In the more than ten years since its discovery, the properties and photoluminescence mechanism of carbon dots have been comprehensively and in-depth understood. research, its application fields have also been greatly expanded. CN201910703197.8 reports a method for preparing yellow fluorescent carbon dots using 2,3-diaminopyridine. Dissolve 2,3-diaminopyridine in water to make a 2,3-diaminopyridine solution. Add acid and bromopyridine. The hydrochloride is then reacted at 180-220°C for 8-10 hours to obtain a reaction liquid containing carbon dots.

References

[1] [Chinese invention] CN201310646336.0 A preparation method of 2,3-diaminopyridine

[2] [China invention, China invention authorization] CN200910133004.6 Improved method for preparing diaminopyridine

[3] [Chinese invention] CN201910703197.8 Method for preparing yellow fluorescent carbon dots using 2,3-diaminopyridine and its products and applications