H- 



tiO- 



H- 



H- 



COOH 

 —OH 

 — H 

 —OH 

 —OH 



SYNTHESIS 

 H OH H Br 



CH2OH 

 D-gluconic 

 acid 



HO— 

 H— 

 H— 



CH2OH 

 D-arabinose 



■H I AcO— 



O 



—OH I > H— 



' H 



CH 



II 

 CH 



—OH 



CH2OAC 



acetobromo- 

 D-arabinose 



CH2OH 



D-arabinal 



CH2NH2 



H— 

 H— 

 H— 



-OH 

 -OH 

 -OH 



CH2OH 



D-ribamine 



+ 

 CH, 



NO, 



CH. 



CH. 



+ 



11 



CH2OH 



D-ribose 



NO, CH. 



NH., CH 



+ 



NH, 



/\/\ 



NH . COOC2H; 



CH3/ ^/ ^NOs 

 I : 2-dimethyl-4 : 5- 



dinitrobenzene I 



CHj ^. .NH . CH2 . (CHOH), . CH2OH 



I 11 CH3. . .N=CH.(CHOH)3.CH20H 



ch/\/Xko2 I ^ I ,, 



CH3/ ^/ \N02 I II 



CH3/ \/ ^ NH . COOC2H5 



NH— CHj . (CHOH) 3 . CH2OH 



CH. 



CH. 



NH . CH2 . (CHOH), . CH2OH 



NH2 



Riboflavine 

 141 



