N-Methyl dicyclohexylamine → 2-tert-butyl-3-(2,2-dimethoxy-ethyl)-6-nitro-1H-indole

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Reaction Conditions

Reaction Steps

2-Bromo-5-nitro-phenylamine (4.9 g, 22.6 mol), Pd2(dba)3 (207 mg, 0.226 mmol), and 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (431 mg, 0.904 mmol) was added in a dry 500 mL round-bottom flask. The flask was evacuated and purged with nitrogen three times. 1,1-Dimethoxy-5,5-dimethyl-hex-3-yne (4.61 g, 27.1 mmol), dicyclohexyl-methyl-amine (14.5 mL, 67.8 mmol) and N,N-dimethylformamide (56.5 mL) was added. The reaction mixture was stirred at 100° C. for 24 h, cooled to room temperature, and filtered through a pad of Celite, which was rinsed with ethyl acetate. The filtrate and wash were combined, washed with water and a saturated sodium chloride solution, dried over magnesium sulfate, filtered and concentrated in vacuo. The crude product was purified by silica gel column chromatography to give the title compound as an orange powder (1.41 g, 20%). LCMS (m/z): 307.1 (M+1).

Provenance & Evidence