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XI. 



ON DESOXY-HYDEOCATECHIN-TETRAMETHYL-ETHER. 



[Preliminary Communication.] 



By HUGH EYAN, D.Sc, and MICHAEL J. WALSH, M.Sc, 

 University College. Dublin. 



[Read Januauy 25. Published May 26, 1916.] 



Gambir catechu, an extract from the twigs of Vhcaria catechu and 

 Uncaria acida, is used for the tanning of skins and the dyeing of cotton 

 or wool. Catechin, the main constituent of the extract, was isolated by 

 van Eisenbeck in 1832. l 



In 1902, A. GL Perkin and E. Yoshitake 2 showed that Gambir catechu 

 contains two different catechins, one melting at 175° C, and the other at 

 235° C, and that catechu — an extract from Acacia catechu — contains another 

 catechin which melts at 204° C. Since these catechins, on decomposition, 

 are resolved into catechol and phloroglucinol, they must be very closely 

 related. 



The formula 



OH 



HO/\/\CH / \ ()H 



I I I \_/ 

 \/\/CHOH 



Oil CH 2 

 proposed by Perkin and Yoshitake for catechin formed the first real attempt 

 to represent graphically the chemical behaviour of catechin. 



This formula is in agreement with the formation of catechin-tetramethyl- 

 ether, catechin-pentacetate, with the decomposition of the substance into 

 catechol and phloroglucinol, with the formation of catechone-trimethylether, 

 and with the possibility of resolving catechin, or its monocarboxyl derivative, 

 into optically active components, as M. Nierenstein 3 has succeeded in doing 

 in the case of the latter substance. 



1 Liebig's Annaleu der Chemie u. Pharm., 1832, i. , p. 243. 



2 Journ. Chem. Sue, 1902, lxxxi., p. 1169. 



3 Liebig's Annaleu der Chemie, 1913, cccxcvi., p. 194. 



§CIENT. PROC. E.D.S., VOL. XV., NO. XI. T 



