Synthesis of 2-(1-Azulenyl)ethanamine Derivatives by Aminoethylation of Azulenes with Aziridines

Abstract Azulene analogs of biological active amines were synthesized. Reaction of azulene or guaiazulene with 1-butanoylaziridine or with 1-butanoyl-2-methylaziridine in the presence of Lewis acid catalyst formed the corresponding N-butanoyl-1-(1-azulenyl)-, N-butanoyl-2-(1-azulenyl)-, and N-butanoyl-2-(1-guaiazulenyl) derivatives of ethanamine, or 1-propanamine, or of 2-propanamine, respectively (5–9). Reaction of guaiazulene with 2-methyl-, or 1,1-dimethylaziridinium, or with 1,1,2,2-tetramethylaziridinium ions gave the corresponding 1-(1-guaiazulenyl)- and 2-(1-guaiazulenyl) derivatives of ethanamine, or 1-propanamine, or of 2-propanamine. 2-(1-Azulenyl)- and 2-(4,6,8-trimethyl-1-azulenyl) derivatives of ethanamine were also obtained by the action of 1,1-diethylaziridinium ion on azulene or on 4,6,8-trimethylazulene. Compounds 5, 6, and 9 were active in vitro in the inhibition of prostaglandin 15-hydroxydehydrogenase and of cyclic AMP-phosphodiesterase.