Methylhydrazine → 1-(4-Chloro-phenyl)-3-[4-hydroxy-3-(2-methyl-2H-pyrazol-3-yl)-phenyl]-urea

Participants

Reaction Steps

To a cooled and stirred solution of methyl hydrazine (1.46 g, 31.6 mmol) in pyridine was added slurry of 1-(4-Chloro-phenyl)-3-(4-oxo-4H-chromen-6-yl)-urea (2.5 g, 7.9 mmol) in pyridine over a period of 10 mins. The reaction mixture was left at this temperature for another 2 hrs and then warmed to room temperature slowly. After 6 hrs the reaction mixture turned clear. The reaction was stirred at this temperature for 18 hrs and pyridine was evaporated. The dark colored residue was dissolved in DMSO and purified using Varian Prep. HPLC system. (The two regioisomers were separated. The fractions containing Compound 119 were dried in vacuo to produce a colorless powder (1.78 g, 47%) 1-(4-Chloro-phenyl)-3-[4-hydroxy-3-(2-methyl-2H-pyrazol-3-yl)-phenyl]-urea. LCMS m/z (%)=343 (M+H, 35Cl 100), 345 (M+H, 37Cl, 32.5). 1H NMR (400 MHz, DMSO-d6) δ: 9.59 (bs, 1H), 8.72 (bs, 1H), 8.48 (bs, 1H), 7.43-7.46 (dd, J=6.8, 2.07 Hz, 2H), 7.41 (d, J=1.83 Hz, 1H), 7.28-7.30 (dd, J=7.13, 2.09 Hz, 2H), 7.26 (d, J=2.72 Hz, 1H), 6.88-6.90 (d, J=9.36 Hz, 1H), 6.21 (d, J=1.84 Hz, 1H), 3.67 (s, 3H).

Provenance & Evidence