Monomeric CON has been structurally characterised by microwave jet spectroscopy and shown to exist in a dominant boat-chair conformation with non-equivalent lone pairs of the oxygen . The energy difference to the next conformation is so large that monohydration is unlikely to switch the energy sequence. Therefore up to two isomers of the monohydrate are expected and the more stable one is of interest in the present challenge. As the energy balance between the two docking isomers could be subtle, we recommend to calculate both and to provide at least the donor OH stretching wavenumber of the more stable one. We are not aware of any vibrational study of the monohydrate of CON.