Hydrochloric Acid → tert-Butyl 3,4-dimethylpiperazine-1-carboxylate

Participants

Reaction Steps

3-Methylpiperazine-1-carboxylic acid tert-butyl ester (5.70 g) obtained from Referential Example 82 was dissolved in methanol (100 mL). To the resultant solution, 10% palladium-carbon (0.59 g), 35% aqueous formalin (9.7 mL), and 1M HCl in ethanol (31.3 mL) were added at room temperature, followed by stirring in a hydrogen atmosphere for 15 hours. After the system was purged with nitrogen, insoluble matter was filtered off, and the solvent of the filtrate was evaporated under reduced pressure. To the residue, chloroform-methanol (9%) was added, and the resultant mixture was alkalinized through addition of aqueous sodium hydroxide, followed by partition. The aqueous layer was extracted with chloroform-methanol (9%). The organic layers were combined and washed with saturated brine, and then dried over sodium sulfate anhydrate, followed by filtration. The solvent was evaporated under reduced pressure, and the residue was purified through silica gel column chromatography (chloroform-methanol), to thereby give the title compound as an oily product (3.10 g, 51%).

Provenance & Evidence