Amezinium metilsulfate

Amezinium metilsulfate (INN, trade name Regulton) is a sympathomimetic drug used for the treatment of low blood pressure. It has multiple mechanisms, including stimulation of alpha and beta-1 receptors and inhibition of noradrenaline and tyramine uptake.

Synthesis
This antidepressant is made from Chloridazon starting material. The halogenation of 2-Butyne-1,4-diol [110-65-6] (1) with chlorine gives Mucochloric acid [87-56-9] (2). Treatment with Phenylhydrazine [100-63-0] (3) gives 1-Phenyl-4,5-dichloro-6-pyridazone [1698-53-9] (4). Addition of ammonia leads to Chloridazon [1698-60-8] (5). Catalytic hydrogenation yields 5-amino-2-phenylpyridazin-3-one [13589-77-0] (6). Alkylation with dimethyl sulfate completed the synthesis of Amezinium metisulfate (7).