1904-31-0, name is 1-Methyl-1H-pyrazol-3-amine, belongs to pyrazoles-derivatives compound, is considered to be a conventional heterocyclic compound, which is widely used in drug synthesis. The chemical synthesis route is as follows. Formula: C4H7N3
General procedure: Amino-pyr azole 1 (0.291 g, 0.003 mol) and an aqueous solution of NaBr (100 mL) (concentrations were as follows: 1 in entries 1 and 2, 2 Min entries 3 and 5-9, and 3 in entry 4) were placed in a cell. In experiment 2, NaHCO3 (0.504 g, 0.006 mol) was added to the solution. The electrolysis was carried out at the following currents: 426 mA for entries 1-4, 213 mA for entry 5, 710 mA for entries 6, 8, and 9, and 852 mA for entry 7. In experiment 9, 48% aqueous solution of HBr was periodically added to the reaction mixture to maintain 7. After passing 2 F of electricity per 1 mole of the starting aminopyrazole 1(Q= 579 C) for entries 1-7or 8 F (Q= 2316 C) for entries 8and 9, the electrolysis was stopped, the reaction mixture was stirred for 1 h and analyzed by TLC (eluent light petroleum ether-ethyl acetate (1 : 1)). Then, the mixture obtained was diluted with concentrated HCl (to 3) and the products were extracted with CHCl3 (3×30 mL). The extracts were combined, dried with anhydrous MgSO4, and concentrated in vacuo. The products were isolated using column chromatography on SiO2 (eluent light petroleum ether-ethyl acetate). The following compounds were isolated: 1,2-bis(1-methyl-1H-pyrazol-3-yl)-diazene (7) (entries 1-7; the product was identified by m.p. 201-202 C (cf. Refs 2 and 4: m.p. 201 C) and the reported 2,41 NMR spectra) and 1,2-bis(4-bromo-1-methyl-1H-pyrazol-3-yl)diazene (8) (entries 8 and 9, the product was identified by NMR spectroscopy and high resolution mass spectrometry). The aqueous layer obtained after extraction was concentrated in vacuo, diluted with NaOH with stirring (to 10), and treated as described above. This resulted in the isolation of 3-amino-4-bromo-1-methyl-1H-pyrazole (6) (entries 1-9; the product was identifi ed by m.p. 97 C (cf. Ref. 10: m.p. 97-98 C) and the reported 51 NMR spectra) and unreacted aminopyr-azole 1(entries 1-8; the starting compound was identified by TLC and NMR spectroscopy).
The synthetic route of 1904-31-0 has been constantly updated, and we look forward to future research findings.
Reference:
Article; Lyalin; Sigacheva; Kokorekin; Dutova, T. Ya.; Rodionov; Petrosyan; Russian Chemical Bulletin; vol. 67; 3; (2018); p. 510 – 516; Izv. Akad. Nauk, Ser. Khim.; 3; (2018); p. 510 – 516,7;,
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