Hydrochloric Acid → 4-(7-Amino-2-methyl-1-oxo-2,3-dihydro-1H-isoindol-4-yl)-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

To a solution of 4-(2-methyl-7-nitro-1-oxo-2,3-dihydro-1H-isoindol-4-yl)-piperazine-1-carboxylic acid tert-butyl ester (5.37 g, 14 mmol) in ethanol (200 mL), iron powder (3.98 g, 70 mmol) and 1N hydrogen chloride (28 mL) are added and the mixture is stirred at 60° C. for 2 hours. The mixture is cooled to room temperature, and then 1N sodium hydroxide (28 mL) is added. After removing insoluble material by filtration, the mixture is concentrated. The residue is extracted twice with dichloromethane. The organic layer is successively washed with water and brine, dried over magnesium sulfate, and evaporated in vacuo to afford 4-(7-Amino-2-methyl-1-oxo-2,3-dihydro-1H-isoindol-4-yl)-piperazine-1-carboxylic acid tert-butyl ester (4.9 g) as pale green amorphous solids in 99% yield. Rf=0.18 (Hexane/AcOEt=111). 1H-NMR (400 MHz, CDCl3, δ, ppm): 1.49 (s, 9H), 2.85 (t, 4H), 3.13 (s, 3H), 3.54 (t, 4H), 4.28 (s, 2H), 5.03 (s, 2H), 6.56 (d, 1H), 6.96 (d, 1H).

Provenance & Evidence