4-Amino-1-Boc-piperidine → tert-Butyl 4-((5-nitrobenzo[d]oxazol-2-yl)amino)piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-methylsulfanyl-5-nitro-benzooxazole (10.0 g, 47.57 mmol, 1.0 equiv) and 4-amino-piperidine-1-carboxylic acid tert-butyl ester (14.29 g, 71.36 mmol, 1.5 equiv) in anhydrous DMAc (50 mL) was heated to 140° C. for 72 h. The solution was concentrated by evaporation under reduced pressure and the crude reaction product purified with column chromatography on silica eluting with ethyl acetate/cyclohexane (1:1) to give 4.1 g (24%) of the title compound. 1H NMR (300 MHz, CDCl3): δ 1.48 (s, 9H), 1.50-1.53 (m, 2H), 2.11-2.20 (m, 2H), 2.87-3.05 (m, 2H), 3.89-4.01 (m, 1H), 4.05-4.16 (m, 2H), 5.51 (d, J=7.5 Hz, 1H), 7.30 (d, J=8.7 Hz, 1H), 8.02 (dd, J=8.7 Hz, J=2.3 Hz, 1H), 8.18 (d, J=2.3 Hz, 1H). 13C NMR (75 MHz, CDCl3): δ 28.40, 32.29, 42.46, 50.88, 79.81, 108.36, 111.99, 116.77, 143.90, 145.23, 152.38, 154.66, 162.69. MS (ISP): 363.5 [M+H]+.

Provenance & Evidence