[CH:1]([C:3]1[CH:18]=[CH:17][C:6]([O:7][C:8]2[N:9]=[CH:10][C:11]([C:14]([NH2:16])=[O:15])=[N:12][CH:13]=2)=[CH:5][CH:4]=1)=O.[CH3:19][CH:20]([CH3:24])[CH2:21][CH2:22][NH2:23].[BH4-].[Na+]>CO>[CH3:19][CH:20]([CH3:24])[CH2:21][CH2:22][NH:23][CH2:1][C:3]1[CH:18]=[CH:17][C:6]([O:7][C:8]2[N:9]=[CH:10][C:11]([C:14]([NH2:16])=[O:15])=[N:12][CH:13]=2)=[CH:5][CH:4]=1Place 5-(4-formylphenoxy)pyrazine-2-carboxamide (0.150 g, 0.617 mmol), 3-methylbutylamine (0.0537 g, 0.617 mmol) and 3 Å molecular sieves in a vial. Add methanol (3.1 mL), cap and stir overnight. Add NaBH4 (in excess over two portions) and stir until the gasses stop evolving. Load the reaction mixture directly onto a 5 g ISCO® pre-load column. Dry the column in a vacuum oven at room temperature. Purify by eluting through a 10 g ISCO® column with 2.0 M NH3 in methanol, ethyl acetate and hexanes to give the title compound (0.0606 g, 31.2%): MS ES+ 315.1 (M+H)+, base peak 228.0 (M−C5H12N)+; HPLC [YMC-Pack Pro C-18 (150×4.6 mm, S-5 microm), 0.1% TFA/acetonitrile in 0.1% TFA/water at 1.0 mL/min, 5-95% over 19 min], tR=8.5 min., 96.4% purity.
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