Methanol → HCID 86614810, compound

Participants

Reaction Steps

Disodium 2,3-dimethyl-3-(4-sulphonatobutyl)-3H-indole-5-sulphonate (1 g), ethyl-p-toluene sulphonate (0.95 ml; 5.56 mmol) and tetramethylenesulphone (10 ml) were heated together at 140° C. for 12 hrs. TLC (silica; 2:1 MeOH; EtOAc) showed the formation of a new product spot (rf=0.8), which turned magenta on standing. The product was precipitated into ethyl acetate and then filtered off and dried in vacuo to give the crude product as a dark purple solid; 1.5 g. The product was purified in multiple shots by HPLC (Vydac protein & peptide C18 (250 mm×25 mm); flow rate 10 ml/min; gradient of 0 to 25% B over 30 mins; eluant A=0.1% TFA in water and eluant B=0.1% TFA in acetonitrile; detection at 220 nm). The fractions containing the desired product were pooled and the solvent removed under reduced pressure. The product was obtained as a pale pink oil (400 mg).

Provenance & Evidence