Chemical Properties
Off-White to pale Yellow Solid
Originator
Nimzox,Rapross Pharmaceuticals
Pvt. Ltd.,India
Uses
An α2-adrenergic agonist; centrally active myotonolytic. A muscle relaxant (skeletal).
Uses
Tizanidine (Zanaflex) is a drug that is used as a muscle relaxant. It is a centrally acting α-2 adrenergic agonist. It is used to treat the spasms, cramping, and tightness of muscles caused by medical problems such as multiple sclerosis, spastic diplegia,
Definition
ChEBI: Tizanidine hydrochloride is a benzothiadiazole.
Manufacturing Process
14 ml of benzoyl chloride are added to a solution of 11.5 g of ammonium
thiocyanate in 150 ml of acetone in an ice bath and the mixture is then stirred
for 10 min. This solution is heated to the boil at reflux together with 19 g of
4-amino-5-chloro-2,1,3-benzothiadiazole. The solution is cooled to room
temperature and diluted with a 4-fold quantity of water. The precipitate is
filtered off and rapidly brought to a boil together with 150 ml of a 2 N
aqueous sodium hydroxide solution and kept at the boil for 5 min. The
solution is cooled to room temperature, is acidified weakly with glacial acetic
acid, the precipitate is filtered off, washed with ether and recrystallized from
methanol. The N-(5-chloro-2,1,3-benzothiadiazol-4-yl)thiourea, obtained and
this is boiled for 1 h together with 9 g of methyl iodide in 150 ml of methanol.
After concentrating by evaporation, crude S-methyl-N-(5-chloro-2,1,3-
benzothiadiazol-4-yl)isothiuronium iodide is obtained. 9.8 g of S-methyl-N-(5-
chloro-2,1,3-benzothiadiazol-4-yl)isothiuronium iodide are heated to the boil
at reflux for 1 h together with 50 ml of methanol and 1.8 ml of ethylene
diamine. The solvent is then removed by evaporation and the moist residue is
boiled at reflux for 1 h together with 20 ml of n-amyl alcohol. The mixture is
subsequently shaken with 50 ml of chloroform and 150 ml of water until all
the material is dissolved. 40 ml of a 2 N aqueous sodium hydroxide solution
are added to the aqueous phase and extraction is effected with 200 ml of
chloroform. The organic phase is dried and concentrated by evaporation. After
recrystallizing the residue from methanol with the addition of some active
charcoal, 4-(2-imidazolin-2-yl-amino)-5-chloro-2,1,3-benzothiadiazole, having a melting point of 221-223°C, is obtained.
The 4-(2-imidazolin-2-yl-amino)-5-chloro-2,1,3-benzothiadiazole hydrochloride
may be obtained by the teaction of 4-(2-imidazolin-2-yl-amino)-5-chloro-
2,1,3-benzothiadiazole with hydrochloric acid.
Brand name
Tizanidine is
INN and BAN.
Therapeutic Function
Muscle relaxant, Spasmolytic
Biological Activity
α 2 -adrenergic receptor agonist. Antinociceptive upon epidural administration in rats (IC 50 = 48 nM). Also binds to imidazoline receptor.
