ove. [0110] Scheme 1 refers to the preparation of compounds of the formula I in two steps from compounds of formula II. Referring to Scheme 1 compounds of the formula III, wherein L is a suitable leaving group such as fluoro, bromo, chloro or mesyl (MeSO2), preferably bromo or chloro, are converted to the corresponding compound of formula II by reaction with hydrazine to form a hydrazino-pyridine,