Reaction #11258

Reaction equation

aldehyde

5-Nitro-1H-indole-2-carbaldehyde

2-chlorobenzyltriphenylphosphonium chloride

→

diene

2-[2-(2-Chlorophenyl)ethenyl]-5-nitro-1H-indole

Conditions

Workup

1. 1
   Otherprepared
2. 2
   Otherdescribed in example 37(at room temperature

Procedure

Reaction of the aldehyde (904) prepared as described in example 454 with 2-chlorobenzyltriphenylphosphonium chloride using the procedure described in example 37(at room temperature) gave the diene (905) as a mixture of E/Z isomers as a yellow solid (95%). Crystallisation from aqueous methanol yielded the pure E-isomer as yellow needles (80%), mp 230–232° C. 1H NMR δ [(CD3)2SO] 12.28 (br s, 1H), 8.55 (d, J=2.3 Hz, 1H), 8.03 (dd, J=9.1, 2.3 Hz, 1H), 7.91 (dd, J=7.8, 1.5 Hz, 1H), 7.32–7.61 (m, 6H), 6.92 (s, 1H). Found: C, 64.59; H, 5.68; N, 9.49. C16H11ClN2O2 requires C, 64.33; H, 5.68; N, 9.49.

Source