The cyclization of a mixture of phenylene-1,2-diamine (I), 2-sulfanylpropionic acid (II) and 2,6-difluorobenzaldehyde (III) in refluxing benzene gives a mixture of the two diastereomers of 1-(2,6-difluorophenyl)-3-methyl-1H,3H-thiazolo[3,4-a]benzimidazole, from which the trans-(racemic)-(IV) isomer has been isolated by silica gel column chromatography. The enantiomeric resolution has been performed by chiral HPLC affording the (1R, 3R)-(IV) isomer, the target compound.