DE1795217

1,169,310. Optical isomers of condensed imidazo - thiazole derivative. IMPERIAL CHEMICAL INDUSTRIES OF AUSTRALIA & NEW ZEALAND Ltd. 2 Aug., 1968 [24 Aug., 1967; 11 Jan., 1968; 18 Jan., 1968], No. 37039/68. Heading C2C. Optically active D- and L-isomers (the L- isomer being particularly suitable for the treatment of helminthiasis) of 6-phenyl-2,3,5,6-tetrahydroimidazo - (2,1-b) thiazole (tetramisole for short) are separated from their racemate by a process which comprises adding to a predominantly aqueous solution of said racemate, or a water-soluble derivative thereof, an optically active isomer of a carboxylic acid or a water-soluble derivative thereof, which acid has a molecular weight greater than 250, forms a salt with one of said tetramisole isomers having a solubility in said aqueous medium considerably lower than that of the corresponding salt of the other tetramisole isomer and wherein the concentration of said racemate in solution is such that said less soluble tetramisole isomer salt crystallizes from said aqueous medium to the substantial exclusion of the other tetramisole isomer salt. A preferred resolving agent is a water-soluble derivative of an optically active isomer of an amino acid, e.g. an N-arylsulphonyl- L(+)- or -D(-)-glutamic acid and the novel L(-)- and D(+)-tetramisole V-arylsulphonyl- L( + )- and D(-)-glutamate salts (the term aryl includes: phenyl-, p-toluene-, p-fluorobenzene-, p-bromobenzene- and p-nitrobenzene-) including the hydrates thereof are described.