Synthesis and Molecular Structure of tert-Butyl 3-oxo-2-oxa-5-azabicyclo[2.2.2]octane-5-carboxylate

The compound tert-butyl 3-oxo-2-oxa-5-azabicyclo[2.2.2]octane-5-carboxylate was synthesized as a cyclic amino acid ester from the corresponding ethyl 2-amino-4-(2-oxiranyl)butanoate HCl salt via an intramolecular lactonization reaction and was characterized by using 1H NMR spectroscopy and high-resolution mass spectrometry. The product was then recrystallized from dichloromethane/diethyl ether and its structure was determined via single crystal X-ray diffraction analysis. The crystal was found to be of the monoclinic space group P21/c (no. 14) with a = 10.217(2) Å, b = 11.676(3) Å, c = 10.273(3) Å, β = 114.186(13)°, and Dcalc = 1.350 g/cm3 at 123 K. The compound has bicyclo[2.2.2]octane structure including a lactone moiety and a piperidine ring, and the two diastereomers of the molecules are present in a 1 : 1 ratio in the crystal