O-Phenylenediamine → (R)-tert-Butyl 3-(2-aminophenylcarbamoyl)piperidine-1-carboxylate

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Reaction Steps

(R)-1-(tert-Butoxycarbonyl)piperidine-3-carboxylic acid (17.45 mmol, 4.0 g) and benzene-1,2-diamine (17.45 mmol, 1.87 g) were added to a 100 mL round-bottomed flask equipped for stirring under nitrogen. DMF (30 mL) and 4-methylmorpholine (52.35 mmol, 5.76 mL) were added and the resultant solution was allowed to stir for 5 min at room temperature. N1-((ethylimino)methylene)-N3,N3-dimethylpropane-1,3-diamine hydrochloride (20.94 mmol, 4.01 g) and 1H-benzo[d][1,2,3]triazol-1-ol (20.94 mmol, 2.83 g) were then added and the reaction was allowed to stir at room temperature for 16 hr. The reaction solution was poured into water and extracted with ethyl acetate. The organic layer was washed three times with water, two times with saturated aqueous sodium bicarbonate, and once with saturated aqueous sodium chloride. The organic layer was collected and dried with Na2SO4. This mixture was then filtered, the filtrate was collected and concentrated and dried in-vacuo affording (R)-tert-Butyl 3-(2-aminophenylcarbamoyl)piperidine-1-carboxylate (7A) as a brownish foam that was carried directly on to the next step without further purification. ESI-MS: m/z 320.4 (M+H)+.

Provenance & Evidence