
%0 Journal Article
%A Li, CP 
%A Blackman, AJ 
%T Cylindricines H-K, Novel Alkaloids From the Ascidian <I>Clavelina cylindrica</I>
%J Australian Journal of Chemistry
%D 1995/05/01
%V 48
%N 5
%P 955-965
%K 
%R https://doi.org/10.1071/CH9950955
%U https://www.publish.csiro.au/paper/CH9950955 
%X Three novel reduced pyrrolo [2,1-j] quinolines (cylindricines H, I and K) and one novel pyrido [2,1-j] quinoline ( cylindricine J) have been isolated from two further Tasmanian collections of the ascidian Clavelina  cylindrica. These alkaloids are all related in structure to cylindricines A-G which have been obtained previously from the same ascidian. Cylindricines H-J are the first acetoxycylindricines obtained. Furthermore cylindricines I and J are isothiocyanates, the first such compounds identified from an ascidian, while cylindricine H is a thiocyanate which, together with cylindricines F and G, are the only ascidian thiocyanates known. Cylindricine K is an &#945;,&#946; -unsaturated ketone with the carbonyl group in the 8-position rather than the more usual 4-position as found in cylindricines A-G. Identification of the new alkaloids was by 1H n.m.r., 13C n.m.r., XHCORR, COSY and Fourier-transform i.r . Spectroscopy as well as high resolution e.i. mass spectrometry. Molecular modelling was used to assign relative stereochemistry. The geographical variation of the cylindricines is also reviewed. 
