At least one equivalent of alcohol, represented by the formula (V) R3 OH, wherein R3 represents a member other than hydrogen or a salt-forming cation, and R1, R2, X, Y and Z are as hereinabove described, is then added to the reaction mixture and the thus prepared mixture heated to reflux at a temperature between 100??? C. and 150??? C. to yield the formula (Ib) 2-(2 -imidazolin-2-yl)pyridine ester