Isoamylamine → 5-{2-Methoxy-4-[(3-methylbutylamino)methyl]phenoxy}pyrazine-2-carboxamide

Participants

Reaction Steps

Place 5-(4-formyl-2-methoxyphenoxy)pyrazine-2-carboxamide (Example 719, Part A) (0.700 g, 2.56 mmol), isoamylamine (0.234 g, 2.69 mmol) and 3 {acute over (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 through 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, and dissolve it in EtOAc (100 mL). Wash the organic solution with 1.0 N NaOH (2×25 mL), dry it over Na2SO4, filter and concentrate to give the title compound (0.484 g, 54.9%): TOF MS ES+ 345.2 (M+H)+, HRMS calcd for C18H25N4O3 345.1927 (M+H)+, found 345.1938, 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=10.1 min, 95.4% purity.

Provenance & Evidence