1-Methylpiperazine → 5-(4-Methyl-piperazin-1-yl)-1,3-dihydro-isoindole-2-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

5-Bromo-1,3-dihydro-isoindole-2-carboxylic acid tert-butyl ester (2.97 g, 10 mmol) was azeotropically dried by evaporation from toluene. Tris(dibenzylideneacetone)dipalladium (0) (228 mg, 0.25 mmol), 2-(di-tert-butylphosphino)biphenyl (149 mg, 0.50 mmol) and sodium tert-butoxide (1.34 g, 13.9 mmol) were added and the flask was purged with nitrogen. Toluene (25 mL) then N-methylpiperazine (1.33 mL, 12 mmol) were added and the mixture was heated to 80° C. for 2 hours. After allowing to cool to r.t. the mixture was diluted with ether, filtered through Celite and concentrated to give a residue that was purified by flash chromatography on silica (2M methanolic ammonia/dichloromethane, 1% to 3% gradient). This afforded the title compound as a brown solid (1.45 g, 46%). 1H NMR (MeOH-d4) 7.15 (1H, m), 6.94-6.88 (2H, m), 4.60-4.54 (4H, m), 3.20-3.17 (4H, m), 2.63-2.60 (4H, m), 2.34 (3H, s), 1.52 (9H, s). MS: [M+H]+ 318.

Provenance & Evidence