Ammonium formate → 4-(4-(piperazin-1-yl)phenyl)-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester

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Reaction Steps

3.5 g of 4-[4-(4-(benzyloxycarbonyl)piperazin-1-yl)phenyl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester are placed in a 250 ml three-necked flask under an inert atmosphere. 66 ml of MeOH, then 1.67 g of ammonium formate followed by 1.41 g of 10% Pd/C (50% in water), are added. The mixture is brought to reflux of the methanol for 1 h 30 minutes and then brought back to ambient temperature. It is filtered on a Whatman filter under an inert atmosphere and then rinsing is carried out numerous times with methanol. The methanol is evaporated under reduced pressure. The mixture is taken up in dichloromethane and the organic phase is washed with the minimum amount of water. The organic phase is dried over sodium sulphate, filtered through a sintered glass filter and evaporated under reduced pressure. 2.5 g of 4-(4-(piperazin-1-yl)phenyl)-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester are obtained in the form of a white solid.

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