A series of arylidene imidazo[2,1-b]thiazoles was synthesized, in order to
investigate the influence of different spatial arrangements of the aryliden
e substituent towards the bicyclic structure of imidazo[2,1-b]thiazole on b
enzodiazepine receptor affinity. 1,2- And 2,3-cyclized derivatives of mono-
and di-substituted Z-5-arylidene-2-thiohydantoins were investigated. As an
example of E isomers E-5-benzylidene-2,3-dihydroimidazo[2,1-b]thiazol-6(5H
)-one was obtained. The spatial arrangement of the arylidene substituent to
ward the bicyclic structure as well as the character of isomers had little
influence on the benzodiazepine receptor affinity of the compounds. It seem
s that the greatest influence on biological activity has the nature and the
number of substituents on the phenyl ring. All investigated imidazo[2,1-b]
thiazoles were less active than previously described arylidene imidazo[2,1-
b]thiazepinones.