The Synthesis and Crystal Structures of Two Hydrogen-Bonded N-Oxides

Abstract: (RS,RS,RS,RS)-3-(N-4′-Methoxyphenyl-N-methylamino)cyclohexane-1,2-diol N-oxide 10 and (1R,2S,3S,4R,7R,7aS,1′R)-1,2-dihydroxy-1,2-O-isopropylidene-3-(1′-hydroxy-2′-tert-butoxy-2′-oxoethyl)-7-(phenylthio)hexahydro-1H-pyrrolizine N(4)-oxide 14 were synthesised and studied by X-ray diffraction. The structure of 10·0.5CHCl3 crystallizes in the monoclinic space group P21/c with cell parameters of a = 22.8016(5) Å, b = 11.9666(2) Å, c = 11.6835(2) Å, β = 99.8698(9)°, V = 3140.75(10) Å3 and Z = 8, whereas N-oxide 14 crystallizes in the orthorhombic space group P212121 with cell parameters of a = 5.8296(1) Å, b = 16.0362(1) Å, c = 23.7167(2) Å, V = 2217.147(19) Å3 and Z = 4. These studies served to establish unambiguously the configurations within these substrates. In both cases, adjacent molecules are linked by a series of O–H···O–N hydrogen-bonds, with the N-oxide moieties participating as hydrogen-bond acceptors, to form tape-like arrangements.