ADVANCED PHYSIOLOGICAL CHEMISTRY 



419 



Secondly, another molecule of phenyl-hydraxine reacts on the last ' CHOH ' 

 group of the hydrazone, expelling water from it and itself losing the H 2 of its 

 NH 2 group, forming an osazone thus : 



CH 2 OH(CHOH) 3 CiHO HJ - C - H 



% \N-NH(C 6 H 5 ) 



+ JEyN NH(C 6 H 5 ) 



The liberated * H' goes to split up more phenyl-hydrazine into aniline and 

 ammonia. If now an osazone be hydrolysed by treating with fuming HC1 it 

 breaks up, phenyl-hydrazine being set free, and a body called an osone resulting. 

 This latter has the formula CH 2 OH - (CHOH) 3 - CO - COH from which it is seen 

 that it contains both an aldehyde and a ketone group. The former of these groups 

 can be converted into the CH a OH group of sugar by treating with a reducing 

 agent. 



CH 2 OH - (CHOH) 3 - CO - COH + H 2 = CH 2 OH - (CHOH) 3 - CO - CH 2 (OH) 

 which is the formula for laevulose (a ketose). 



The aldoses can thus be changed into the ketoses, and if the aldose obtained by 

 condensation of HCHO (formaldehyde) be used as the starting-point an interesting 

 synthesis from a simple aldehyde to a more complex one and then to a ketose is 

 illustrated. 



The various sugars have also been artificially prepared by careful 

 oxidation of the corresponding alcohols and by reduction of the 

 corresponding acids. There are three hexatomic alcohols differing 

 from one another in their constitutional formulae. From each of these 

 a different aldose or ketose can be produced by oxidation, and these 

 latter can be further oxidised to form three different mono-basic acids, 

 or further still, to form three di-basic acids, thus : 



The constitutional formula for aldose is : 

 H H H H H 



H 



I I I I I I 

 H C C C C C C 



OH OH OH 01 



>-/ >-/ v^ 



)HOHO 



It is seen from this formula that, there are four C. atoms on to which four 

 different groups or substitutes are attached. These are, therefore, 



1 Monobasic acids have formula CH 2 OH - (CHOH) 4 - COOH. 



2 Dibasic COOH- (CHOH) 4 - COOH. 



