
%0 Journal Article
%A Clark-Lewis, JW 
%A Mahandru, MM 
%T Flavan derivatives. XXX. Synthesis of racemic peltogynol trimethyl ether and its <I>cis-cis</I>-stereoisomer
%J Australian Journal of Chemistry
%D 1971/03/01
%V 24
%N 3
%P 549-562
%K 
%R https://doi.org/10.1071/CH9710549
%U https://www.publish.csiro.au/paper/CH9710549 
%X Synthesis of (±)-peltogynol trimethyl ether [(±)-trans-trans-7,6?,7?- tri-methoxyisochromano(4?,3?:2,3)chroman-4-ol and its (&amp;)-cis-cis- stereoisomer are described. (+)-Peltogynol tetramethyl ether is shown to be the trans-trans-4,7,6?,7?-tetramethyl ether, and acid-catalysed etherification of the (±)-cis-cis-stereoisomer of peltogynol trimethyl ether with methanol is shown to yield the (±)-2,3-cis-3,4-trans- 4,7,6?,7?-tetramethyl ether. Oxidation of cis-cis-2?-hydroxymethyl- 7,4?,5?-trimethoxyflavan-3,4-diol with manganese dioxide gave 3(3?)- hydroxy-7,6?,7?-trimethoxyisochromano(4?,3?:2,3)chroman-4-one (a hemiacetal) and 2?-formyl-7,4?,5?-trimethoxyflavonol. Similar oxidation of trans-trans-2?-hydroxymethyl-7,4?,5?-trimethoxyflavan-3,4-diol gave minor quantities of the hemiacetal and 2?-formyl-7,4?,5?- trimethoxyflavonol, and yielded mainly the 2,3-trans-3-hydroxy- flavanone. N.m.r. data are presented for the compounds described. 
