fazadinium bromide

Originator

Fazadon,Duncan Flockhart,UK,1976

Manufacturing Process

(a) 1-Acetamido-3-methyl-2-phenylimidazo[1,2-a]pyridinium bromide - A mixture of 2-(2-acetylhydrazino)pyridine (2 g) and 2-bromopropiophenone (2.84 g), in ethanol (10 ml) was heated in an open flask in a bath at 160°C to 170°C until the ethanol had evaporated; the residual melt was then heated for a further 0.25 hour. After cooling, the residual gum was triturated with acetone and the resulting solid (2.8 g) recrystallized from ethanol-ether giving the bromide as colorless prisms, MP 232°C to 234°C.
(b) 1-Amino-3-methyl-2-phenylimidazo[1,2-a]pyridinium bromide - A solution of the acetamido compound (2.78 g) in 24% hydrobromic acid (12 ml) was boiled under reflux for 1 hour. The solution was then evaporated under reduced pressure and the residue dissolved in methanol. Addition of ether precipitated the bromide which crystallized from ethanol as colorless prisms, MP 243°C to 244°C (1.7 g).
(c) 1,1'-Azobis[3-methyl-2-phenyl-1H-imidazo[1,2-a]pyridinium]dibromide - A warm (50°C) solution of the N-amino compound (0.6 g) in water (10 ml) was treated with saturated bromine water (70 ml) and the precipitated orange solid filtered off and washed with water. The orange solid was sucked dry and then boiled with acetone (30 ml) until the suspended solid became yellow. Absolute acetone (10 ml) was then added and the solution filtered giving the dibromide (0.57 g) which crystallized from water as the yellow dihydrate, MP 215°C to 219°C (softened at 196°C).

Therapeutic Function

Muscle relaxant