Crystal structure and absolute configuration of (4S,5R,6S)-4,5,6-trihydroxy-3-methylcyclohex-2-enone (gabosine H)

Abstract

The molecule of the title keto carbasugar, C7H10O4, is formed by a cyclohexene skeleton with an envelope conformation, substituted by carbonyl, methyl and hydroxyl groups. The crystal structure is controlled mainly by a combination of strong O—H...O and weak C—H...O hydrogen bonds, forming nearly perpendicular chains running parallel to the [110] and [-110] directions. This perpendicularity is caused by a tetragonal pseudosymmetry influenced by the similarity between theaandbaxes, the value of 90.9770 (10)° of the β angle and the action of a 21screw axis, which transform each chain into its corresponding nearly orthogonal one.