anti-2-Hydr­oxy-2-methyl-1-tetra­lone oxime: X-ray and density functional theory study

Crystals of the title racemic compound, C11H13NO2, consist of two types of mol­ecules (conformers); one mol­ecule has an exocyclic OH group in an equatorial position and the other has this group in an axial position. Consequently, the hydrogen‐bond schemes for the two mol­ecules are different. The mol­ecules with equatorial OH groups create infinite parallel chains (formed by the same enantio­mer), connected by centrosymmetric dimers of mol­ecules (of mixed enantio­mers), both with axial OH groups. Possible inter­conversion of the conformers and the flexibility of the mol­ecule were studied by means of different MP2 and density functional theory (DFT) methods. The optimization of the structure by the DFT method confirmed the types of the hydrogen bonds.