Cl.[CH3:2][CH:3]([O:5][C:6]1[CH:11]=[CH:10][C:9]([C:12]2[C:16]([CH:17]=[O:18])=[CH:15][NH:14][N:13]=2)=[CH:8][CH:7]=1)[CH3:4].C([O-])([O-])=O.[K+].[K+].Br[CH:26]1[CH2:29][CH2:28][CH2:27]1.O>C(#N)C.CCOC(C)=O>[CH:26]1([N:14]2[CH:15]=[C:16]([CH:17]=[O:18])[C:12]([C:9]3[CH:10]=[CH:11][C:6]([O:5][CH:3]([CH3:2])[CH3:4])=[CH:7][CH:8]=3)=[N:13]2)[CH2:29][CH2:28][CH2:27]1A mixture of 3-[4-(propan-2-yloxy)phenyl]-1H-pyrazole-4-carbaldehyde hydrochloride (250 mg, 0.9 mmol) and K2CO3 (626 mg, 4.5 mmol) in acetonitrile (5 ml) was stirred at 0-5° C. for 1 h. Bromocyclobutane (158 mg, 1.16 mmol) was added and the reaction mixture stirred at ambient temperature for 34 h. The reaction was poured into water (200 mL) and extracted with EtOAc (50 mL×3). The combined extracts was washed with brine (100 mL), dried, and concentrated under vacuum. The residue was purified by SGC using Hexane: EtOAc (0%-40%) as eluent to afford 1-cyclobutyl-3-(4-isopropoxyphenyl)-1H-pyrazole-4-carbaldehyde (218 mg, Yield: 71%) as a white solid. LCMS (method C): RT=2.54 min, m/z=285.2 [M+H]+.
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