Reactions of 1-(3-aryl-3-oxopropenyl)azulenes and 1-cinnamoylazulenes with malononitrile: Synthesis of 1-(2-aryl-4-pyridyl)azulenes and 1-(4-aryl-2-pyridyl)azulenes

Article abstract of DOI:10.1002/jhet.5570370501

The reactions of 1-formyl-3-methoxycarbonylazulene (1) with acetophenones 3a-e gave 1-(3-aryl-3-oxopropenyl)-3-methoxycarbonylazulenes 4a-e which reacted with malononitrile in the presence of sodium methoxide to afford 1-(2-aryl-4-pyridyl)-3-methoxycarbonylazulenes 9a-d, except for 4'-nitro-substituted compounds. Heating of the compounds 9a-d in 100% phosphoric acid yielded 1-(2-aryl-4-pyridyl)azulenes 10a-d. In a similar manner, 1-(4-aryl-2-pyridyl)azulenes 12a-I and 1-[4-(2-furyl)- and 4-(2-thienyl)-2-pyridyl)]azulenes 14a,b were obtained.