[Cl:1][C:2]1[N:7]=[N:6][C:5]([C:8]([OH:10])=O)=[CH:4][CH:3]=1.C(N(C(C)C)CC)(C)C.O.O[N:22]1[C:26]2[CH:27]=[CH:28][CH:29]=[CH:30]C=2N=N1.CN(C)CCCN=C=NCC.C1(CCN)CC1>ClCCl>[CH:28]1([CH2:27][CH2:26][NH:22][C:8]([C:5]2[N:6]=[N:7][C:2]([Cl:1])=[CH:3][CH:4]=2)=[O:10])[CH2:29][CH2:30]1To a solution of 6-chloropyridazine-3-carboxylic acid (15.8 mmol) in dichloromethane (95 mL) was added diisopropylethylamine (46.7 mmol), 1-hydroxybenzotriazole monohydrate (23.7 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (23.7 mmol) under nitrogen atmosphere at ambient temperature. The resulting mixture was stirred for 15 minutes and 2-cyclopropylethylamine (20.2 mmol) was added. After stirring for 36 hours at ambient temperature, the reaction mixture was diluted with dichloromethane (100 mL), then washed with water and dried over anhydrous Na2SO4. The solvent was removed in vacuo. Purification via column chromatography (30% ethyl acetate in hexanes) afforded the title compound (8.70 mmol). Yield 55%.
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