p-Toluenesulfonic acid → HCID 19599436, compound

Participants

Reaction Steps

A stirred solution of methyl 2-aminoindole-3-carboxylate (I. Forbes et al, J. Chem. Soc. Perkin I, 1992, 275) (0.5 g, 0.0026 mole) in xylene (10 ml) was treated with 1,1,3,3-tetramethoxypropane (0.43 g, 0.0026 mole) and a few crystals of 4-toluenesulphonic acid and heated under reflux for 2.5 h. The mixture was concentrated in vacuo and the residue dissolved in chloroform (25 ml), washed with water (2×10 ml), dried (MgSO4) and concentrated in vacuo to leave a dark orange solid. This was purified by chromatography on silica gel eluting with ethyl acetate to afford the title compound (D19) as an orange solid (0.23 g, 35%).

Provenance & Evidence