CC1[N:3]([C:8]2[CH:12]=[C:11]([CH:13]3[CH2:16][O:15][CH2:14]3)[NH:10][N:9]=2)C(C)=CC=1.CCO.NO.Cl.C([O-])(O)=O.[Na+]>O>[O:15]1[CH2:16][CH:13]([C:11]2[NH:10][N:9]=[C:8]([NH2:3])[CH:12]=2)[CH2:14]1Into a 250-mL 3-necked round-bottom was placed 3-(2,5-dimethyl-1H-pyrrol-1-yl)-5-(oxetan-3-yl)-1H-pyrazole (4.0 g, 18.4 mmol, 1.0 equiv.), EtOH (100 mL), water (40 mL), and NH2OH.HCl (10.3 g, 148.2 mmol, 8.0 equiv.), followed by the addition of NaHCO3 (9.9 g, 117.8 mmol, 6.4 equiv.) portionwise. The resulting solution was stirred at 100° C. for 24 h, then cooled to 30° C. and concentrated in vacuo. The residue was diluted with 150 mL of THF. The solids were collected by filtration and dissolved in 200 mL of EtOH, filtered and the filtrate concentrated in vacuo. The residue was purified by chromatography on neutral alumina eluting with a DCM/MeOH gradient (1 to 10% MeOH) to afford 0.5 g (19%) of 5-(oxetan-3-yl)-1H-pyrazol-3-amine (91) as a white solid.
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