Indole-2-carb-oxy-lic acid (0.50 g, 3.1 mmol) was dissolved in SOCl2 (19 ml) at 0°C. After stirring for 1 h, the solution was rotary evaporated, and the resulting oil was added to absolute ethanol (17 ml) at room temperature. After stirring overnight, the solution was vacuum filtered to yield ethyl 1H-indole-2-carboxyl-ate as a beige solid, which was recrystallized from methanol to yield 0.54 g (2.9 mmol, 93%) of the product[1].
Synthesis Reference(s)
Chemical and Pharmaceutical Bulletin, 39, p. 1152, 1991 DOI:10.1248/cpb.39.1152