Drumm — The Constitution of Oatechin : Part I. 43 



energetic reduction of catechiu tetramethyl ether obtained an oily product 

 which, on further methylation, formed a crystalline pentaniefchyl ether which 

 melted at SS-S-d" C. Freudenberg (Ber. d. Deutsch. Chem. Ges., 1920, liii, 

 1427), in fact, claims to have proved this pentamethyl ether identical with 

 2--J:'6v3''4''-pentamethoxy-a7-diphenyI-propane, thereby establishing an 

 (17-diphenyl-propane structure for catechin itself. N. Nierenstein (Jour. 

 Chem. Soc, 1920, cvii, pp. 971-1151), however, challenges Freudenberg's 

 results, and at the same time he himself asserts that he has proved 

 V. Kostanecki's catechin reduction product (just referred to) to be identical 

 with 3-4-2'-4''6''-pentamethoxy-aa-diphenyl-propane. The controversy be- 

 tween these two workers has not yet been finally settled. On completion of 

 the work at present in hand the writer hopes to be able to decide between 

 an oa- and ay-diphenyl-propane formula for catechin. 



When a solution of catechin tetramethyl ether (1 mol.) in carbon 

 disulphide is treated with a molecular equivalent of phosphorus pentachloride, 

 hydrogen chloride is at once evolved, and the corresponding chloride of 

 catechin obtained in very good yield. The reaction may be represented 

 thus : — 



C19H21O5 (OH) + P . CI5 = CigH^jOjCl + POClg + HCl. 



This chloride consists of colourless prisms which melt at 112'^ C. (when 

 heated rapidly) with evolution of hydrogen chloride. When catechin chloride 

 is heated with pyridine, it loses liydrogen chloride, and yields a colourless 

 crystalline compound melting at 135° C. The results of analysis of this latter 

 compound prove it to have the formula CsHooOj. 



It is proposed to name this compound dehydro-catechin tethramethyl ether 

 — formula (iii). 



III. IV. 



When the solution of dehydro-catechin tetramethyl ether (1 mol.) in 

 chloroform is treated with bromine (2 mols.), hydrogen bromide is evolved, 

 a bright red crystalline solid at the same time separating from the solution. 

 Though analyses of this compound, agreeing closely with one anotlier, could 

 not be obtained, the results, nevertheless, indicated a monobromide structure 

 for the body. 



For reasons about to be given, a benzepyranol formula (iv) has been 

 assigned to this bromide. The formation of such a compound from dehydro- 



[A- 2] 



