Towards Squalamine Mimics: Synthesis and Antibacterial Activities of Head-to-Tail Dimeric SterolPolyamine Conjugates

Four dimeric sterolpolyamine conjugates have been synthesized from the homo- and hetero-connection of monomeric sterolpolyamine analogs in a head-to-tail manner. These dimeric conjugates show strong antibacterial activity against a broad spectrum of Gram-positive bacteria, whereas their corresponding activities against Gram-negative bacteria are relatively moderate. Though no significant difference was observed in the activities of these conjugates, cholic acid-containing dimeric conjugates generally exhibit higher activities than the corresponding deoxycholic acid-derived analogs. This is in contrast to the finding that a monomeric deoxycholic acid-spermine conjugate was more active than the corresponding cholic acid-derived analog.