Triethyl phosphite → Tetraethyl [[2,2'-bipyridine]-4,4'-diylbis(methylene)]bis(phosphonate)

Participants

Reaction Steps

A chloroform (10 mL) solution of (3) (1.5 g, 4.4 mmol) and 15 mL of triethylphosphite was refluxed for 3 hours under nitrogen. The excess phosphite was removed under high vacuum, then the crude product was purified by column chromatography on silica gel (eluent ethyl acetate/methanol 80/20) yielding 1.6 g (80%) of (4). 1H NMR (300 MHz, CDCl3) δ ppm: 1.29(12H, t, 3JHH=7 Hz, 4 POCH2CH3), 3.23 (4H, d, 2JPCH=22 Hz, 2CH2P), 4.09 (8H, dq, 3JPOCH=7 Hz, 3JHH=7 Hz, 4 POCH2CH3), 7.35-7.38 (2H, m, aryl H on C5 and C5′), 8.34-8.37 (2H, m, aryl H on C3 and C3′), 8.62 (2H, d, 3JHH=5 Hz, aryl H on C6 and C6′). 31P NMR (CDCl3) δ ppm: 25.37. Elemental analysis C20H30N2O6P2: calcd. C 52.63, H 6.63, N 6.14%, found C 52.83, H 6.59, N 6.01%.

Provenance & Evidence