[ ] 



Y. 



l^OTE ON THE ACTION OF EMULSINE ON 

 /S-GLYCOSIDES. 



By HUGH RYAN, D.Sc, E.R.U.I., and GEORGE EBRILL, B.A., 



Catholic University School of Medicine, Dublin. 

 Read June 25. Ordered for Publication June 27. Published July 25, 190G. 



In a previous communication^ we have described the syntheses of 

 some "glycosides derived from arabinose by the action of phenols and 

 naphthol. Owing to lack of material at the time, we were unable to 

 determine the behaviour of enzymes towards these substances. The 

 method described by us for the preparation of the arabinosides was 

 similar to that previously used for the syntheses of the glucosides of 

 the three cresols, /8-naphthol and carvacrol, and of the galactoside of 

 a-naphthol.- 



In the latter experiments the glycosides produced were easily 

 hydrolysed by emulsine, and were, therefore, assigned to the /8-series. 

 The syntheses of the pentosides being in every respect analogous to 

 those of the ^-hexosides, we feel justified in regarding the former as 

 /5-compounds, and are supported in this view by the behaviour of 

 a- and /?-acetochlorohexoses towards alkaline solutions. In the absence 

 of alkali, an a-acetoclilorohexose yields an a-hexoside, and a 

 )8-compound gives a ^-hexoside ; but, in the presence of alkali, both 

 substances yield a /5-hexoside. Even if our aceto-chloro-arabinose 

 had been an a-derivative, it should, under the conditions of the 

 experiments, have yielded /3-glycosides. 



Since members of the j8-series are characterised by the ease with 

 which emulsine hydrolyses them, and the only known synthetical 

 glycosides obtained from pentoses and phenols are those got by us, we 

 deemed it essential for the completion of our work to see if emulsine is 

 inactive towards phenolic pentosides. Emil Eischer has already 

 shown that emulsine is inactive towards alcoholic pentosides. 



For our purpose, tubes containing aqueous solutions of 



1 Proc. Royal Irish Academy, vol. xxiv., Sec. B., Part iv., p. 379. 

 ■■^Ryan, Jour. Chem. Soc, 1899, p. 1054 ; Ryaii and Mills, Jour. Chem. Soc, 

 1901, p. 704. 



R.I. A. PKOC, VOL. XXVI., SEC. 7f."^ G 



