Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Methyl 3-<jats:italic>O</jats:italic>-α-<jats:sc>d</jats:sc>-glucopyranosyl 2-acetamido-2-deoxy-α-<jats:sc>d</jats:sc>-galactopyranoside as a monohydrate, C<jats:sub>15</jats:sub>H<jats:sub>27</jats:sub>NO<jats:sub>11</jats:sub>·H<jats:sub>2</jats:sub>O, crystallizes in space group P2<jats:sub>1</jats:sub>2<jats:sub>1</jats:sub>2<jats:sub>1</jats:sub>, with four molecules in the unit cell. It constitutes the methyl glycoside of the carbohydrate part of the teichoic acid type polysaccharide from <jats:italic>Micrococcus</jats:italic> sp. A1, in which the disaccharides are joined through phosphodiester linkages. The conformation of the disaccharide is described by the glycosidic torsion angles ϕ = − 31° and ψ = + 1°, and the hydroxymethyl groups of the constituent monosaccharides are present in the <jats:italic>gg</jats:italic> and <jats:italic>gt</jats:italic> conformations for the sugar residues having the <jats:italic>gluco</jats:italic>- and <jats:italic>galacto</jats:italic>-configuration, respectively. For the <jats:italic>N</jats:italic>-acetyl group at C2 of the galactosamine residue the torsion angle τ<jats:sub>H</jats:sub> = 147°, i.e., the amide proton has an antiperiplanar relationship to H2 of the sugar ring. The structure shows extensive hydrogen bonding along the a-direction, including the water molecule, and forms sheets with hydrophilic interactions within the sheets as a result of hydrogen bonding between disaccharides as well as hydrophobic interactions between the sheets, in particular, amongst methyl groups of the <jats:italic>N</jats:italic>-acetyl group of the α-<jats:sc>d</jats:sc>-Gal<jats:italic>p</jats:italic>NAc residue in the disaccharides.</jats:p>
<jats:p><jats:bold>Graphical Abstract</jats:bold></jats:p>
<jats:p>The structure of the title disaccharide as a monohydrate, C<jats:sub>15</jats:sub>H<jats:sub>27</jats:sub>NO<jats:sub>11</jats:sub>·H<jats:sub>2</jats:sub>O, which shows extensive hydrogen bonding as well as hydrophobic interactions, was determined from minute crystals using synchrotron radiation and verified by solid state DFT calculations using plane waves.</jats:p>