Powdered sodium hydroxide (3.2 g) was added in a single portion to a vigorously stirred solution of ethyl 3-benzylthioindole-2-carboxylate (2.48 g), 3,4-dichlorobenzyl chloride (1.71 g) and tetra-n-butylammonium hydrogensulphate (0.5 g) in dichloromethane (100 ml). The reaction was stirred for 6 hours then partitioned between 2M HCl and ethyl acetate. Combined organic extracts were dried (MgSO4) and concentrated in vacuo and the residue purified by column chromatography using iso-hexane:5% ethyl acetate as eluent to give the product as a white crystalline solid (2.26 g, 60%); NMR d (CD3SOCD3) 1.32 (t, 3H), 4.00 (s, 2H), 4.25 (q, 2H), 5.60 (s, 2H), 6.78 (d, 1H), 7.04 (m, 2H), 7.10-7.38 (m, 8H), 7.80 (d, 1H); M/z (+) 470 (M+), 426, 424.
