CHEMISTRY OF RIBOSE AND DEOXYRIBOSE 53 



yielded the free sugars. The major component was 2-deoxy-D-ribose and this 

 was isolated as 7V-phenyl-2-deoxy-D-ribosylamine, from which the parent 

 sugar was easily regenerated. Another method for the preparation of 2- 

 deoxy-D-ribose, using 2,3-isopropylidene-D-glyceraldehyde as an initial 

 material has been outlined briefly by Overend and Stacey.^^^ The glycer- 

 aldehyde derivative was condensed with acetaldehyde in the presence of 

 anhydrous potassium carbonate and the products were subjected to mild 

 acidic hydrolysis to yield 2-deoxy-D-ribose and 2-deoxy-D-xylose. D-Arabi- 

 nose has been converted into 2-deoxy-D-ribose in 3 % overall yield by the 

 following sequence of reactions :"^^ by heating in pyridine D-arabinose was 

 converted into ribulose which was isolated as its nitrophenylhydrazone 

 and reduced as such with Raney nickel catalyst to the 2-amino-2-deoxy- 

 pentitols. The amino-alcohols were converted into the deoxy pentose by 

 treatment with nitrous acid. 2-Deoxy-D-ribose was isolated as its benzyl- 

 phenylhydrazone. 



2. Identification 



In addition to the usual methods of carbohydrate identification, and 

 the preparation of suitable derivatives (anilide, benzylphenylhydrazone, 

 etc.), several color tests are available to test for this deoxypentose. Methods 

 of identification of this sugar have recently been reviewed thoroughly by 

 the authors.'* 



Furthermore, many of the color tests used to identify deoxyribonucleic 

 acid depend on the sugar component of the inicleic acid. These color tests 

 are described in Chapter 9. With the Dische-^" diphenylamine reagent, 2- 

 deoxyribose gives an intense blue coloration. The test is not specific for 

 2-deoxyribose, but is given by 2-deoxypentoses generally^^^ ■ ^^^ and depends 

 upon conversion of the 2-deoxysugar under acidic conditions into co-hy- 

 droxylevulinaldehyde, which reacts with diphenylamine to give a blue- 

 colored dyestuff. 



3-Deoxy- and 2,3-dideoxyribose (but not 4-deoxyribose) also give faint 

 blue colors with the diphenylamine reagent, but in these cases it is neces- 

 sary to heat for a longer time than is required for 2-deoxyribose. The trypto- 

 phane reaction, introduced by Cohen-^^ for the detection and estimation of 

 deoxyribonucleic acids, is given equally well by 2-deoxyribose. In the rec- 



2«8 W. G. Overend and M. Stacey, J. Sci. Food Agr. 1, 168 (1950). 



289 Y. Matsushima and Y. Imanaga, Nature 171, 475 (1953); Bull. Chem. Soc. (Japan) 



26, 506 (1953). 

 "oz. Dische, Mikrochemie 8, 4 (1930). 

 29' R. E. Deriaz, M. Stacey, Ethel G. Teece, and L. F. Wiggins, Nature 157, 740 (1946) ; 



J. Chem. Soc. 1949, 1222. 

 292 W. G. Overend, F. Shafizadeh, and M. Stacey, J. Chem. Soc. 1950, 1027. 

 2" S. S. Cohen, J. Biol. Chem. 156, 691 (1944). 



