Hydrochloric Acid → Methyl 1-amino-4-chloro-1H-pyrrole-2-carboxylate, hydrochloride salt

A mixture of sodium hydride (60%, 1.51 g, 38 mmol) and methyl 4-chloro-1H-pyrrole-2-carboxylate (Tetrahedron Letters, 1979, 27, 2505–2508; 4.80 g, 30 mmol) in DMF (40 mL) at 0° C. was stirred for 20 min, then was added 2, 4-dinitrophenolamine (Tetrahedron Lett. 1968, 16, 1909–1910 and J. Heterocyclic Chem. 1967, 413, 7.24 g, 36 mmol), and the reaction mixture was stirred at rt overnight. Water (100 mL) was added to the mixture, and the product was extracted with EtOAc (3×120 mL), the EtOAc solution was washed with 10% LiCl solution (2×120 mL), brine (120 mL), dried over MgSO4 and concentrated in vacuo to give the crude product as a brown oil. This crude product was treated with 4 N HCl in dioxane (8 mL) in Et2O (60 mL), the precipitated solid was collected, washed with Et2O and dried to give the title compound (5.40 g, 85%): 1H NMR (DMSO-d6) δ 7.17 (d, 1H, J=2.2 Hz), 6.68 (d, 1H, J=2.2 Hz), 3.74 (s, 3H).

1. stirringthe reaction mixture was stirred at rt overnight
2. extractionthe product was extracted with EtOAc (3×120 mL)
3. washthe EtOAc solution was washed with 10% LiCl solution (2×120 mL), brine (120 mL)
4. dry with materialdried over MgSO4
5. concentrationconcentrated in vacuo
6. customto give the crude product as a brown oil
7. customthe precipitated solid was collected
8. washwashed with Et2O
9. customdried

ORD record

ord-fe0e8901477d4f068bfeae42429d55d4

Source dataset

uspto-grants-2006_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07030118B2