37660-64-3

General procedure for the synthesis of 4,6-dichloro-3-nitro-2-pyridinamine from 2-amino-4,6-dichloropyridine: 2-amino-4,6-dichloropyridine (4.48 g, 27.48 mmol) was added in batches to concentrated sulfuric acid (6 mL) and fuming nitric acid (1.2 mL) was added slowly and dropwise at 5 °C. The reaction mixture was stirred continuously for 10 h at 5 °C. After completion of the reaction, the reaction was quenched with ice water and the pH was adjusted to 7 to give 3.55 g of yellow solid 4,6-dichloro-3-nitro-2-pyridinamine washed with methanol (yield: 62.1%). Melting point: 208°C. 1H-NMR (300MHz, CDCl3), δ (ppm): 6.84 (s, 1H), 6.25 (br, 2H).

[1] Bioorganic and Medicinal Chemistry Letters, 2017, vol. 27, # 15, p. 3395 - 3398
[2] Patent: WO2014/128465, 2014, A1. Location in patent: Page/Page column 102
[3] Patent: WO2018/75937, 2018, A1. Location in patent: Paragraph 00317; 00318; 00588