Tiamenidine (BAN, USAN, INN, also known as thiamenidine, Hoe 440) is an imidazoline compound that shares many of the pharmacological properties of clonidine. It is a centrally-acting ñ<sub>2</sub> adrenergic receptor agonist (IC<sub>50</sub> = 9.1 nM). It also acts as an ñ<sub>1</sub>-adrenergic receptor agonist to a far lesser extent (IC<sub>50</sub> = 4.85 üM). In hypertensive volunteers, like clonidine, it significantly increased sinus node recovery time and lowered cardiac output. It was marketed (as tiamenidine hydrochloride) by Sanofi-Aventis under the brand name Sundralen for the management of essential hypertension.
Reaction of thiourea 1 with methyl iodide gives the corresponding S-methyl analogue (2), followed by heating with ethylenediamine, completes the synthesis of tiamenidine (3).