of Guanidine with Sugars. 81 



[ a z>] = 0*98° ; the fructose compound has an initial specific rota- 

 tion of [a D ] = - 58-3°, falling to [a D ] = - 187° in 8 days. Maltose 

 and rhamnose in their compounds with guanidine show a similar 

 muta-rotation. An aqueous solution of the glucose guanidine 

 compound has its optical activity changed to that of glucose 

 on addition of hydrochloric acid. The extreme solubility in water, 

 and insolubility in neutral organic solvents render the recrystal- 

 lisation of these substances a matter of great difficulty, but as 

 they were precipitated in a minutely crystalline form from ethylic 

 alcohol analyses were made of the precipitate, which had been 

 washed with absolute alcohol and ether. Only in the case of 

 rhamnose have we been able to obtain a derivative which can be 

 recrystallised with difficulty from ethyl alcohol. Their melting 

 points are low, between 94 — 98° with effervescence. On drying at 

 40° the substances soften and become yellow in colour. The yields 

 of these guanidine compounds are excellent ; from 18 grams of 

 glucose dissolved in 1500 c.c. of absolute alcohol nearly 23 grams 

 of the additive product were precipitated ; the yield is quantita- 

 tive ; moreover the alcoholic filtrate was inactive and changed the 

 colour of a Fehling's solution only slightly on boiling. Heating 

 to 100° modified the properties of these substances in a striking 

 manner; they melt and alcohol is evolved, but no ammonia; their 

 reducing power towards Fehling's solution is diminished, and they 

 give no alkaline reaction in aqueous solution. Their behaviour 

 towards phenylhydrazine acetate is unchanged, except in the case 

 of the galactose derivative, which gives no longer an osazone, 

 and does not react with picric acid to give guanidine picrate. 

 In all the cases examined the percentages of carbon and nitrogen 

 increase on melting the substances. We have not been able to 

 obtain the fused products in a crystalline form, and have analysed 

 them directly. The maltose compound loses four molecules of 

 water besides alcohol, those of rhamnose and galactose one molecule 

 of water. 



We are unable at present to assign with certainty constitu- 

 tional formulae to these substances, but the investigation is being 

 continued, and we hope that a careful examination of the products 

 obtained by heating the substances to 100° C. will throw light on 

 their constitution. In this preliminary notice we desire to express 

 our thanks to the Government Grant Committee of the Royal 

 Society for a grant covering the cost of the material of this 

 research. 



