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IX. 



THE CONSTITUTION OF CATECHIN.— PAET II. 



ON DEOXYCATEGHIN-TETEAMETHYLETHEE AND DIHYDEO- 

 VERATEYLIDENE-3-5-DIMETHOXYCOUMAEANONE. 



By JAMES J. DETJMM, M.Sc, MAEY M. MacMAHON, M.Sc, 



AND 



HUGH EYAN, D.Sc, 



Xliiiversity College, Dublin. 



[Read NovKMBEU 30, 1923. Piililislied May 23, 1924.] 



In 1902 it was suggested by A. G. Perkiu aud E. Yoshitake (Jour. Chem. 

 Soc, 1902, Ixxxi, p. 1169) that catechiu is a derivative of l-pheuylelironiane. 

 Shortly afterwards, St. von Kostanecki and Y. Lampe (Ber. Dtsch. Chem. 

 Ges., 1906, xx.xix, p. 4007) were led to the conclusion that catechin is 

 derived from ^-benzylcoumarane. The latter conception of the constitution 

 of catechin appeared to be supported by the conversion of catechin-tetrani- 

 ethylether, by energetic reduction and methylation, into deoxyhydrocatechiii- 

 pentamethylether, which von Kostanecbi and l.ampe (ibid., 1907, xl, p. 720) 

 formulated as the peutamethoxy derivative of wi-ethylphenyl-phenyl-methane. 

 Some doubt as to the correctness of this formula for the reduction product 

 arose when it was shown (H. Eyau and M. J. Walsh, Proc. Eoyal Dublin 

 Soc, 1916, N.S., XV, p. 113) that an oily product, obtained by tlie reduction 

 of veratroyl-etliyl-phloroglucinol-trimethylether, did not crystallise when 

 inoculated with crystals of deoxycatechiii-pentamethylether. 



Later, M. Nierenstein (Jour. Chem. Soc, 1920, cxvii.p. 972), who obtained 

 the reduction product of veratroyl-ethyl-phloroglucinol-trimethylether in a 

 crystalline condition, showed that it was not identical with deoxyhydro- 

 catecliin-pentamethylether. It has since been claimed by M. Nierenstein 

 (Jour. Cliem. Soc, 1920, cvii, pp. 971, 1151) that deoxyhydrocatechiii- 

 pentamethylether is identical with 3-4-2'-4'-6'-pentamethoxy-a-a-diphenyl- 

 propane. K. Ereudenberg (Per. Dtsch. Chem. Ges , 1920, liii, p. 1427), on tlie 

 other hand, claims to have shown that this pentanietliylether is identical with 

 2'4'6'3''4'-pentamethoxy-a7-diphenyl-propane. 



Eeccntly one of us (J. J. Druuim, Proc. Eoyal Irish Acad., 1923, xxxvi, 

 B, p. 41) showed tliat catechin-tetrametliyletlier could be converted into a 



p., I. A. PROC. VOL. XX>:VI, SECT. B. ( ^ | 



