Trifluoroacetic acid → methyl 11-cyclohexyl-6-hydroxy-8-methoxy-6H-isoindolo[2,1-a]indole-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

The general methods below were used with the following experimental procedures until indicated otherwise: LCMS data: Stop time: Gradient time+1 minute; Starting conc: 0% B unless otherwise noted; Eluent A: 5% CH3CN/95% H2O with 10 mM NH4OAc (for columns A and D); 10% MeOH/90% H2O with 0.1% TFA (for columns B and C); Eluent B: 95% CH3CN/5% H2O with 10 mM NH4OAc (for columns A and D); 90% MeOH/10% H2O with 0.1% TFA (for columns B and C); Column A: Phenomenex 10 4.6×50 mm C18; Column B: Phenomenex C18 10 3.0×50 mm; Column C: Phenomenex 4.6×50 mm C18 10μ; Column D: Phenomenex Lina C18 5μ 3.0×50 mm; Column E: Phenomenex 5μ 4.6×5.0 mm C18. To a slurried solution of methyl 2-bromo-3-cyclohexyl-1H-indole-6-carboxylate (4.3 g, 13 mmol), 4-methoxy-2-formylphenylboronic acid (3.0 g, 17 mmol) and LiCl (2.2 g, 51 mmol) in EtOH/toluene (1:1, 100 mL) was added Pd(PPh3)4 (1.4 g, 1.3 mmol) and then 1M Na2CO3 (aq.) (32 mL, 32 mmol). The reaction solution was flushed with nitrogen and heated at 100° C. for 3 h and cooled to rt. The reaction was concentrated to remove EtOH, diluted with H2O (200 mL) and extracted with EtOAc (2×150 mL). The combined organics were washed with brine (100 mL), dried (MgSO4), filtered and concentrated to dryness. The residue was triturated with CH2Cl2 and the solids were collected by filtrated and washed with Et2O and CH2Cl2 to yield methyl 11-cyclohexyl-6-hydroxy-8-methoxy-6H-isoindolo[2,1-a]indole-3-carboxylate (3.0 g, 8.0 mmol, 63%) as a yellow solid which was used without further purification. LCMS: m/e 374 (M+H)+, ret time 3.09 min, column B, 3 minute gradient.

Provenance & Evidence