THE STRUCTURE OF RHYNCOPHYLLINE

Abstract

It is shown that hydrolysis of rhyncophylline with dilute hydrochloric acid gives rhyncophyllal (C19H24O2N2), which contains an aldehyde group but no longer contains the methoxyl, the isolated double bond, and the carbomethoxy group originally present in the alkaloid. Rhyncophyllal is reduced by sodium borohydride to the corresponding alcohol, rhyncophyllal, and this is further reduced by lithium aluminum hydride to dihydrodesoxy-rhyncophyllal (C19H28ON2), which shows the properties of an aromatic amine. Reduction of rhyncophyllal by the Wolff-Kishner reaction gives rhyncophyllane (C19H26ON2), which, when dehydrogenated over palladium–charcoal, yields 3,4-diethylpyridine. Direct dehydrogenation of rhyncophyllal produces β-collidine. On the basis of these as well as previously described results a total structure for rhyncophylline is derived.