A seven-step, stereoselective, total synthesis of the ladybug defensive substance myrrhine (5) from 2,4,6-collidine is presented. Successive alkylation and acylation of 2,4,6-collidine followed by ketalization provides 2-(3-[2-(1,3-dioxolanyl)]propyl)-6-(2-methyl-2-[1,3-dioxolanyl]methyl)-4-methylpyridine (14). Sodium–alcohol reduction gives the corresponding all-cis piperidine 17. Hydrolysis of 17 followed by acid-catalyzed cyclization provides ketone 26. Reduction of the carbonyl group in 26 gives myrrhine (5). Cyclization using pyrrolidine – acetic acid gives a mixture of ketones (26 and 31). Reduction of 31 gives (±)-hippodamine (4). Oxidation of (±)-hippodamine with peracid gives (±)-convergine (3).
Das aus 2,4,6‐Kollidin (I) erhältliche Acetal (II) wird in drei Schritten in das Bis‐äthylenacetal(III) übergeführt, aus dem bei Reduktion mit Natrium in Isoamylalkohol als Hauptprodukt das all‐cis‐Piperidin (IV) erhalten wird.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.