CHEMISTRY OF RIBOSE AND DEOXYRIBOSE 59 



is 2-deoxy-D-ribose-l-arsenate, which decomposes in aqueous media to 

 2-deoxy-D-ribose and arsenate ions. 



Allerton et al.^^^ have succeeded in synthesizing some phosphoric acid 

 esters of 2-deoxy-L-ribose. Phosphorylation of methyl 2-deoxy-/3-L-ribo- 

 pyranoside with diphenylphosphorochloridate afforded the crystalline 

 3,4-62sdiphenyl phosphate. Hydrogenation of this compound in the 

 presence of Adam's catalyst afforded the syrupy 3,4-diphosphoric acid 

 derivative which was characterized by the formation of its acridine and 

 cyclohexylamine salts. Very mild acidic hydrolysis resulted in cleavage of 

 the glycosidic methyl group without simultaneous scission of the phosphate 

 residues and in this way 2-deoxy-L-ribose-3,4-diphosphate was obtained. 

 By a similar series of reactions 2-deoxy-L-ribose-3 , 5-diphosphate was pre- 

 pared from methyl 2-deoxy-a!,|3-L-ribofuranoside. Furthermore 2-deoxy- 

 L-ribose-3-phosphate and 2-deoxy-L-ribose-5-phosphate were prepared and 

 isolated as salts. 



2-Deoxy-D-ribose-5-phosphate may be involved in the biosynthesis of 

 this deoxypentose. [Cf. Glock, Chapter 22.] The suggestion was made by 

 Hough and Jones^'^ that deoxypentoses may arise from the aldol-type 

 condensation of acetaldehyde and glyceraldehyde. Racker^'^ has deduced 

 evidence which indicates a similar route for the enzymic synthesis of deoxy- 

 pentose from triose phosphate and acetaldehyde. Extracts of E. coli, C. 

 diphtheriae and S. fecalis prepared by sonic disintegration of the bacterial 

 cells, or by grinding with alumina, are capable of catalyzing the reversible 

 reaction : 



glyceraldehyde phosphate + acetaldehyde ^ deoxypentose phosphate 



By combining the enzyme (phosphodeoxyriboaldolase) bringing about 

 this change with purified phosphoriboaldolase from yeast, Racker^'^'' was 

 able to demonstrate the long-sought conversion of D-ribose into deoxy-D- 

 ribose; e.g. 



D-ribose-5-phosphate > deoxy-D-ribose-5-phosphate 



It is apparent that a triose phosphate is the common intermediate between 

 D-ribose and 2-deoxy-D-ribose in metabolism. 

 d. Other Derivatives and Reactions 



The action of acid on 2-deoxyribose results in the formation of co-hy- 

 droxylevulinaldehyde and then levulinic acid.^^^ Oxidation with bromine 

 water follows the normal course and affords 2-deoxyribonic acid."-"® 

 Similarly, oxidation can be achieved with barium hypoiodite in the presence 



3" R. Allerton, W. G. Overend, and M. Stacey, Chemistry & Industry 1952, 952. 



312 L. Hough and J. K. N. Jones, Nature 167, 180 (1951). 



3'3 E. Racker, (a) Nature 167, 408 (1951); (b) J. Biol. Chem. 196, 347 (1952). 



