Synthesis, structural characterization and solubility of 2-(1-substituted-1,11-undecylidene)-5-arylimino-Δ3-1,3,4-thiadiazolines

A series of novel 2-(1-substituted-1,11-undecylidene)-5-arylimino-Δ3-1,3,4-thiadiazolines (4) were synthesized and their structure was characterized by 1H NMR, 13C NMR and elemental analysis. Their solubility in both polar and non-polar solvents is significantly improved owing to the introduction of ethyl or methylthio group at cyclododecyl ring as compared with parent compounds [1, 2-(1,11-undecylidene)-5-arylimino-Δ3-1,3,4-thiadiazolines]. However, their fungicidal activity against Rhizoctonia solani is less than that of parent compounds. X-ray diffraction analysis of a representative compound (4d) showed that the conformation of 12-membered ring is still [3333], in which the ethyl group present at the side-exo position and the thiadiazoline ring at the corner carbon. The thiadiazoline plane is perpendicular to the cyclododecyl one.