Triethylamine → 8-Benzyl-3,8-diaza-bicyclo[4.2.0]octane-3-carboxylic acid tert-butyl ester

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Reaction Steps

To a cooled to 0° C. solution of 3-benzylamino-4-hydroxymethyl-piperidine-1-carboxylic acid tert-butyl ester (3.65 g, 11.4 mmol) and triethylamine (4.77 mL, 34.2 mmol) in THF (60 mL), was added drop-wise methane sulfonyl chloride (1.7 g, 14.8 mmol) at 0° C. The reaction mixture was warmed to room temperature and stirred for 1 h, then Cs2CO3 (5.0 g, 15.4 mmol) was added. The reaction mixture was heated to 60° C. for 18 h. The reaction mixture was cooled to ambient temperature and filtered. The filtrate was washed with H2O (2×100 mL), the organic layer was separated and the aqueous layer was extracted with EtOAc (2×100 mL). The combined organics were dried (Na2SO4), filtered, and concentrated under reduced pressure to yield the crude title compound (3.38 g). The crude product was purified (FCC, SiO2, 4% acetone, dichloromethane) to yield pure title compound (2.88 g, 84%). MS (ESI) mass calcd. for C18H26N2O2, 302.42; m/z found, 303.2 [M+H]+. 1H NMR (CDCl3): 7.35-7.15 (m, 5H), 4.02-2.80 (m, 9H), 2.48-2.36 (m, 1H), 1.95-1.65 (m, 2H), 1.56-1.32 (m, 10H).

Provenance & Evidence