3-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)-5-nitro-1H-indole → 4-(5-nitro-1H-indol-3-yl)cyclohex-3-en-1-one

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Reaction Steps

Compound 120 (0.26 g, 0.557 mmol) was treated with 1 N aqueous HCl solution at room temperature and the resulting solution was refluxed for 2 h. The reaction was brought to room temperature, filtered and washed with water (5 mL). The solvent was evaporated and crude was recrystallised from ethanol/ether to obtain compound 121 (0.23 g, 94%) as a solid in 2:3 ratio of diastereomers. 1H NMR (DMSO-d6) δ 1.22-1.29 (m, 3H), 1.53-1.62 (m, 2H), 1.80-2.16 (m, 6H), 2.74-3.23 (m, 4H), 7.08 (d, 1H, J=8.4 Hz), 7.24-7.52 (m, 3H), 7.68-7.72 (m, 1H), 8.14-8.18 (m, 2H), 8.59 (s, 1H), 8.97-9.09 (m, 2H), 9.64 (s, 1H), 11.20, 11.27 (2s, 1H), 11.42 (s, 1H); ESI-MS m/z (%): 367 (MH+ for free base, 18), 322 (100), 184 (19), 119 (39); ESI-HRMS calculated for C21H27N4S (MH+, free base), calculated: 367.1959; observed: 367.1950.

Provenance & Evidence