Diisopropylaniline → N-[(6-Bromopyridin-2-yl)methyl]-2,6-diisopropylaniline

Participants

Reaction Steps

A solution of 85.0 g (457 mmol) of 6-bromopyridine-2-carbaldehyde and 80.9 g (457 mmol) of 2,6-diisopropylaniline in 1000 ml of ethanol was refluxed for 8 h. The obtained solution was evaporated to dryness, and the residue was re-crystallized from 200 ml of methanol. In argon atmosphere, to thus obtain 113.5 g (329 mmol) of N-[(1E)-(6-bromopyridin-2-yl)methylene]-2,6-diisopropylaniline, 33.16 g (526 mmol) of NaBH3CN, 9 ml of AcOH and 1000 ml of methanol were added. This mixture was refluxed for 12 h, then cooled to room temperature, poured into 1000 ml of water, and crude product was extracted with 3×200 ml of ethyl acetate. The combined extract was dried over Na2SO4 and evaporated to dryness. The residue was purified by flash chromatography on silica gel 60 (40-63 um, eluent: hexane-ethyl acetate=10:1, vol.). Yield 104.4 g (66%) of a yellow oil. Anal. calc. for C18H23BrN2: C, 62.25; H, 6.68; N, 8.07. Found: C, 62.40; H, 6.87; N, 7.90. 1H NMR (CDCl3): δ 7.50 (m, 1H, 4-H in Py), 7.38 (m, 1H, 5-H in Py), 7.29 (m, 1H, 3-H in Py), 7.05-7.12 (m, 3H, 3, 4, 5-H in 2, 6-iPr2C6H3), 4.18 (s, 2H, CH2NH), 3.94 (br.s, 1H, NH), 3.33 (sept, J=6.8 Hz, 2H, CHMe2), 1.23 (d, J=6.8 Hz, 12H, CHMe2).

Provenance & Evidence