NOVEL ANTHELMINTIC AGENTS .3. 1-(2-ARYLVINYL)PYRIDINIUM SALTS

Anthelmintic activity has been discovered among some trans-1-(2-arylvinyl)pyridinium salts which are structurally analogous to trans-1,4,5,6-tetrahydiO-1-methyl-2-[2-(2-thienyl)vinyl] pyrimidine (pyrantel). The structure-activity relationships in this new series parallel very closely those found in the pyrantel group; i.e., (i) the decreasing order of potency among various aryl systems is 2-thienyl > phenyl > 2-furyl; (ii) ortho substituents on the aryl moiety are compatible with activity while substituents elsewhere result in the loss of activity or a reduction in potency; (iii) a 1-(2-arylvinyl) compound is generally more potent than the corresponding 1-(2- arylethyl) analog; (iv) an α-methyl substituent on the vinylene bridge results in the loss of activity; and (v) substitution of the pyridine ring by methyl at the 2 position is compatible with activity; methyl substitution elsewhere on the pyridine ring results in the loss of activity. Among the more potent compounds in this series are 1-[2-(2-thienyl)-vinyl]pyridinium bromide (62), 1-[2-(3-methyl-2-thienyl)vinyl]pyridinium bromide (63), and 1-(2-methylstyryl)pyridinium bromide (66). © 1969, American Chemical Society. All rights reserved.