The solvent effect on the ground-state energy difference of meridine (enol
form) and meridin-12(13H)-one (keto form) is examined by use of AM1 acid CO
SMO methods. The results show that solvents stabilize the keto form more th
an the enol form. In apolar solvents, the enol form is the predominant spec
ies, whereas in polar solvents, the enol and keto forms are present in an a
lmost equal amount.