反应详情

A solution of 3-cyclohexenyl-1H-indole-6-carboxylic acid (1 eq., prepared as described in Example 1, Step 1) in dry DCM (0.19 M) was treated with tert-butyl N,N′-diisopropylimidocarbamate (2 eq.). The resulting clear solution was heated at reflux for 36 h. Addition of a further equivalent of isourea was required after 16 h to drive the reaction to completion. After cooling down the solvent was evaporated giving a residue that was purified by silica gel chromatography (Flashmaster Personal, PE:EtOAc, 30:1) affording tert-butyl 3-cyclohexyl-1H-indole-6-carboxylate (75%) 1H NMR (300 MHz, DMSO-d6, 300 K) δ 1.22-1.53 (m, 5H), 1.54 (s, 9H), 1.70-1.86 (m, 3H), 1.95-1.98 (m, 2H), 2.69-2.86 (m, 1H), 7.29 (s, 1H), 7.49-7.57 (m, 2H), 7.93 (s, 1H), 11.09 (s, 1H); MS (ES+) m/z 300 (M+H)+.

1. temperatureThe resulting clear solution was heated
2. temperatureat reflux for 36 h
3. customthe reaction to completion
4. temperatureAfter cooling down the solvent
5. customwas evaporated
6. customgiving a residue that
7. customwas purified by silica gel chromatography (Flashmaster Personal, PE:EtOAc, 30:1)