Ethyl (2Z)-3-cyanoprop-2-enoate → Ethyl 4-cyano-1,2,3,4,5,10-hexahydrocyclopenta[a]carbazole-5-carboxylate

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Reaktionsschritte

2-(Cyclopenten-1-yl)indole (13.6 g, 74 mmol), ethyl cis-3-cyanoacrylate (17.8 g, 142 mmol) and BHT (70 mg) were heated to 180° C. under nitrogen for 30 min. The volatiles were removed by kugelrohr distillation at 110° C. and 0.8 mm to afford 19.7 g of an amber-brown tar. Addition of ether (50 mL) afforded a precipitate of a single isomer of white crystalline ethyl 4-cyano-1,2,3,4,5,10-hexahydrocyclopenta[a]carbazole-5-carboxylate (1.89 g, 8.2% yield); mp 192-195° C. NMR (CDCl3) δ 7.91 (s, 1H), 7.46 (d, 1H), 7.34 (d, 1H), 7.12 (m, 2H), 4.31 (d, 1H0, 4.32 (m, 2H), 4.20 (d, 1H), 3.46 (t, 1H), 3.30 (q, 1H), 2.80 (m, 1H), 2.3-1.4 (m, 6H), 1.34 (t, 3H). Anal. Calcd for C19H20N2O2: C, 74.00; H, 6.54; N, 9.08. Found: C, 73.84; H, 6.53; N, 9.03.

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