Synthesis and vasodilation activity of some novel bis(3-pyridinecarbonitrile) derivatives

A variety of bis(2-alkoxy-6-aryl-3-pyridinecarbonitriles) 4a-m were prepared via reaction of bis(2-propen-1-ones) 3a-g with malononitrile in the appropriate alcohol in the presence of KOH. The reaction was assumed to take place via Michael addition followed by cyclization due to the alkoxide nucleophilic attack at one of the nitrile groups. This assumption was substantiated by the reaction of ylidenemalononitrile 5 with the corresponding acetophenone 2 in the appropriate alcohol in the presence of KOH. The starting bis(2-propen-1-ones) 3e and f were prepared stereoselectively as E,E'-geometric isomer via condensation of bisbenzaldehyde 1 with substituted acetophenones 2e and f in ethanolic KOH solution. Vasodilating activity screening of the synthesized compounds 4a-g and 4i-m utilizing isolated rat's thoracic aorta pre-contracted by norepinephrine hydrochloride exhibited that many of the tested compounds reveal considerable vasodilating properties, especially 4e and f which reveal remarkable activities.