Propynal → 3-[4,5-Bis(4-fluorophenyl)-2-(1-methylethyl)-1H-imidazol-1-yl]-2-propenal

Participants

Reaction Steps

To a solution of 4,5-bis(4-fluorophenyl)-2-(1-methylethyl)-1H-imidazole (492 mg) in dry THF under nitrogen was added propiolaldehyde (0.97 ml) and the reaction mixture heated to reflux. Further quantities of propiolaldehyde were added in portions (3×1.1 g) during successive 2 h periods. The reaction mixture was concentrated and the deep red residue was purified by FCC eluting with system A (1:4) to give the title product (398 mg) as an off-white solid and as a 1:1 mixture of geometric isomers. δ(CDCl3) 9.48 (d, 1H, J 7.5 Hz, cis CHO), 9.40 (d, 1H, J 7.5 Hz, trans CHO), 7.5 (d, 1H, J 15 Hz, trans CH=CHCHO), 7.45-6.85 (m, 17H, aromatic protons and cis CH=CHCHO), 5.98 (t,1H,J 7.5 Hz, cis CH=CHCHO), 5.63 (dd, 1H, J 15 and 7.5 Hz, trans CH=CH CHO), 3.25 (septet, 1H, J 7 Hz, CH(CH3)2 of trans isomer), 3.05 (septet, 1H, J 7 Hz, CH(CH3)2 of cis isomer).

Provenance & Evidence