3,3-Dimethylbutylamine → 5-{4-[(3,3-Dimethylbutylamino)methyl]-2-methoxyphenoxy}pyrazine-2-carboxamide

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Reaction Steps

Place 5-(4-formyl-2-methoxyphenoxy)pyrazine-2-carboxamide (Example 719, Part A) (0.700 g, 2.56 mmol), 3,3-dimethylbutylamine (0.272 g, 2.69 mmol) and 3 Å molecular sieves in a vial. Add methanol (12.8 mL), cap and stir overnight. Add NaBH4 (0.0969 g, 2.56 mmol) and stir until the gasses stop evolving. Load the reaction mixture directly onto a 25 g ISCO® pre-load column. Dry the column in a vacuum oven at room temperature. Purify by eluting t-rough a 40 g ISCO® column with 5% to 20% (2.0 M NH3 in methanol) in ethyl acetate over 45 minutes. Concentrate the fraction containing the product, then take it up in EtOAc (100 mL). Wash the organic solution with 1.0 N NaOH (2×25 mL), dry it over Na2SO4, filter and concentrate. Dissolve the product in ether:dichloromethane (5:1) (25 mL), add hexanes (20 mL), and then concentrate to about a quarter of the volume. Filter the precipitate to give the title compound (0.421 g, 45.9%): TOF MS ES+ 359.2 (M+H)+, HRMS calcd for C19H27N4O3 359.2083 (M+H)+, found 359.2093, time 0.38 min; HPLC [YMC-Pro pack C-18 (150×4.6 mm, S-5 microm), 0.05% TFA/acetonitrile in 0.05% TFA/water at 1.0 mL/min, 10-20% over 5 min, 20-95% over 18], tR=11.0 min, 98.0% purity.

Provenance & Evidence