1-(Pyridin-3-yl)-4,5-dihydro-1H-pyrazol-3-amine → 1-(Pyridin-3-yl)-1H-pyrazol-3-amine
Reaction equation
[N:1]1[CH:6]=[CH:5][CH:4]=[C:3]([N:7]2[CH2:11][CH2:10][C:9]([NH2:12])=[N:8]2)[CH:2]=1>[O-2].[Mn+4].[O-2].C(#N)C>[NH2:12][C:9]1[CH:10]=[CH:11][N:7]([C:3]2[CH:2]=[N:1][CH:6]=[CH:5][CH:4]=2)[N:8]=1Participants
4
Reactant 1
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 60 °C
Procedure
To a 3-neck, round bottomed flask (100 mL) was charged 1-(pyridin-3-yl)-4,5-dihydro-1H-pyrazol-3-amine (1.00 g, 6.17 mmol) and acetonitrile (20 mL). Manganese(IV) oxide (2.68 g, 30.8 mmol) was added, causing an exotherm from 20° C. to 25° C. The reaction was stirred at 60° C. for 18 hours, after which it was filtered through a Celite® pad and the pad was rinsed with acetonitrile (20 mL). Water (20 mL) was added to the combined filtrates and the resulting mixture was concentrated to 10 mL. Water (20 mL) was added and the resulting mixture was again concentrated to 10 mL. The resulting suspension was stirred at 20° C. for 18 hours and filtered. The filter cake was rinsed with water (2×5 mL) and dried to afford the title compound as a brown solid (0.68 g, 69%): mp 169-172° C.; 1H NMR (400 MHz, DMSO-d6) δ 9.07-8.82 (m, 1H), 8.33 (dd, J=4.6, 1.5 Hz, 1H), 8.24 (d, J=2.6 Hz, 1H), 8.00 (ddd, J=8.4, 2.7, 1.4 Hz, 1H), 7.42 (ddd, J=8.5, 4.6, 0.8 Hz, 1H), 5.80 (d, J=2.6 Hz, 1H), 5.21 (s, 2H); 13C NMR (101 MHz, DMSO-d6) δ 157.67, 144.68, 138.00, 136.22, 128.30, 123.95, 123.17, 97.08; ESIMS m/z 161 ([M+H]+).