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Phenylhydrazine (80 mmol), 3-benzoylpropionic acid (1a) (80 mmol), and 12 ml of concentrated H2SO4 in 100 ml of ethanol were heated at reflux for 24 hours. The cooled reaction mixture was poured onto 500 g of ice, and the resulting mixture was extracted with ether (300 ml×2). Workup gave a red oil, which was purified by column chromatography (silica gel, ethyl acetate/n-hexane=1/5) to afford 15.2 g (73%) of ethyl 2-phenyl-3-indole acetate (8) as a pale yellow solid. mp: 61°-62° C.; IR (KBr) 3370, 1718, 1585, 1458 cm-1 ; 1H NMR (CDCl3, 300 MHz), 8 8.17 (s, 1H), 7.67-7.71 (m, 3H), 7.47 (dd, 2H), 7.40 (dd, 2H), 7.40 (dd, 2H), 7.20 (m, 2H), 4.12 (q, 2H), 3.98 (s, 2H), 1.07 (t, 3H), mass spectrum (15 ev) m/Z 279 (M), 206, 179, 128, 102, 77, 58, 43; exact mass calcd for C18H17NO2 279.1259; found 279.1259.

1. temperatureat reflux for 24 hours
2. customThe cooled reaction mixture
3. extractionthe resulting mixture was extracted with ether (300 ml×2)
4. customWorkup gave a red oil, which
5. customwas purified by column chromatography (silica gel, ethyl acetate/n-hexane=1/5)