30 PROXIMATE CONSTITUENTS OF PLANTS 



ill) CH2OH CH2OH 



CHOH CHOH 



I I 



CHOH = CHOH + NH3 + CfiH^NHg 



CHOH CHOH 

 I 



CHOH + H2N.NHC6H5 CO 



CH : N . NHCgH^ CH : N . NHCgHg 



I 



Hypothetical oxyhydrazone. 



(iii.) CH2OH CH.OH 



I I 



CHOH CHOH 



I I 



CHOH CHOH 



I = I +H2O 



CHOH CHOH 



CO + H,N . NHC.H, C : N . NHCeH^ 



CH : N . NHCgHs CH : N . NHCeH^ 



i 



Glucosazone. 



It was largely owing to the possibility of forming 

 crystalline osazones from difficultly crystallisable sugars 

 that Emil Fischer was enabled to complete his work on 

 the chemistry of this group of compounds. 



(c) Reactions with Silver Nitrate and Cobalt Nitrate. — 

 In addition to reducing alkaline copper tartrate to 

 cuprous oxide, other alkaline solutions of metallic 

 salts {e.g.^ Ag, Bi), undergo an analogous change on 

 treatment with certain sugars ; for example, ammoniacal 

 silver nitrate is reduced to the metallic state (silver 

 mirror) by glucose and fructose, although cane sugar 

 produces no such reduction. Again, on adding 1 5 c.c. 

 of a sugar solution to 5 c.c. of a 5 per cent, solution of 

 cobalt nitrate and mixing with 2 c.c. of a 50 per cent. 



