Abstract: The invention concerns the use of a compound of formula (I) ##STR1## wherein R and R.sub.1, each independently, represent a hydrogen atom or a methyl group, and its pharmaceutically acceptable acid addition salts, as free radical scavengers. The pharmaceutical compositions containing these compounds may be employed in the treatment and/or prevention of pathological processes involving cell damage due to the formation of free radicals.The invention also concerns the compounds of formula (I) wherein at least one of R and R.sub.1 is methyl, which are new compounds, as well as the process for the preparation thereof and the pharmaceutical compositions containing them.

Abstract: The invention relates to derivatives of 2,3-dihydro 3-imino-pyridazine responding to general formula: ##STR1## in which: A represents an atom of oxygen or of sulfur;R.sub.1 represents a lower alkyl group, or an aromatic group selected from:the phenyl group;the phenyl groups mono- or poly-substituted by a halogen group, a lower alkyl group, a lower alkoxy group, a nitro group, a hydroxy or methylenedioxy group;the naphthyl group;the furyl group;the thienyl group or the pyridyl group;R.sub.2 and R.sub.3 each designate independently hydrogen or a lower alkyl group; a phenyl group, or R.sub.2 and R.sub.3, taken together, constitute, with the 2 atoms of the pyridazinic cycle to which they are bonded, a benzene ring, and their pharmaceutically acceptable salts. Application: antidepressants or psychotonics.