Lithium diisopropylamide → 5-methoxy-2-[(E)-2-(2-nitrophenyl)ethenyl]-1H-indole

Participants

Reaction Steps

The 5-methoxy-1H-indole-2-carbaldehyde (1) was reacted with (2-nitrobenzyl)(triphenyl)phosphonium chloride using the procedure described in example 37, except that the ratio of LDA:aldehyde was 1.37:1 and the reaction time was 5 h, to give (after crystallisation from CH2Cl2/hexane) the diene (536) as red-orange crystals (the pure E isomer) (47%), mp 136–138° C. 1H NMR (CDCl3) δ 8.25 (br s, 1H), 7.98 (dd, J=8.2, 1.2 Hz, 1H), 7.78 (dd, J=7.9, 1.0 Hz, 1H), 7.61 (td, J=7.6, 0.9 Hz, 1H), 7.41 (d, J=16.3 Hz, 1H), 7.39 (td, J=7.8, 1.3 Hz, 1H), 7.27 (m, 1H), 7.13 (d, J=16.3 Hz, 1H), 7.04 (d, J=2.4 Hz, 1H), 6.90 (dd, J=8.8, 2.5 Hz, 1H), 6.62 (d, J=1.8 Hz, 1H), 3.86 (s, 3H). Found: C, 69.44; H, 4.49; N, 9.70. C17H14N2O3 requires C, 69.38; H, 4.79; N, 9.52.

Provenance & Evidence