CHEMISTRY OF RIBOSE AND DEOXYRIBOSE 19 



method has been introduced by Lee and Berger and their co-workers.*^- ^^ 

 The technique is based upon the fact that arylamine-A^-ribosides (e.g., 

 A^-phenyl-D-iibosylamine) prepared by dissolving the crude ribose in an 

 aqueous-alcohoHc solution of an arylamine, form "complex salts" with 

 the soluble salts of alkali metals. (The sugar-A^-glycoside forms a loose 

 combination with the inorganic salt.) The arylamine-A^-riboside may be 

 extracted- from this complex with dioxane and decomposed by boiling water 

 containing a trace (0.25 %) of acetic acid. Alternatively, aqueous hydrolysis 

 of the arylamine-A^-riboside, catalyzed by bases, or in the presence of alde- 

 hydes such as benzaldehyde, regenerates the original amine and D-ri- 

 bose.**'*'' After removal of the arylamine, either by steam distillation or 

 by forming the benzylidene derivative, pure crystalline ribose may be 

 obtained in yields of 70-90 %. Triacylribose derivatives can be prepared 

 by this procedure from arylamine A^-acylated ribosides. Thus, pure 2,3,4- 

 tri-0-acetyl-D-ribose was obtained by hydrolysis of the 2,3, 4-tri-O-acety 1- 

 A''-phenyl-a-D-ribosylamine^° which resulted from the anilination of crude 

 2,3,4-tri-O-acetyl-D-ribose and purification of the "anilide" via a "com- 

 plex salt." 



The preparation of D-ribose from yeast nucleic acid has been extensively 

 investigated. Levene and Clark^' developed a method involving hydrolysis 

 of the nucleic acid with ammonia at an elevated temperature and pressure. 

 From the resultant mixture of nucleosides, adenosine and guanosine were 

 separated, purified and subjected to further hydrolysis to give D-ribose. 

 Levene^'- described a preparation of crystalline D-ribose by acidic hydrolysis 

 (0.05 A'^ sulfuric acid at the reflux temperature for 2 hours) of pure ash-free 

 guanosine. It was considered essential by Levene to work with a colorless 

 hydrolysate, if pure ribose is required. For the hydrolysis of nucleic acid, 

 Phelps^' replaced ammonia by magnesia and heated the mixture at 145° 

 for 4 hours. Magnesium-containing phosphates are removed by filtration 

 and then guanosine precipitates directly and adenosine is recovered from 

 the mother liquors as the picrate. Acidic hydrolysis of either guanosine 

 or adenosine picrate results in the liberation of D-ribose. (See also Bates 

 and associates'^ for preparative details of D-ribose from nucleic acid.) 



8« J. Lee, U. V. Solmssen, and L. Berger, U. S. Pat. 2,384,103 (Sept. 4, 1945). 

 " L. Berger and J. Lee, J. Org. Chem. 11, 84 (1946). 



8* L. Berger, U. V. Solmssen, F. Leonard, Ed. Wenis, and J. Lee, J. Org. Chem. 11, 

 91 (1946). 



89 J. Lee, E. Fells, and L. Berger, U. S. Pat. 2,383,977 (Sept. 4, 1945). 



90 J. Lee and L. Berger, U. S. Pat. 2.384,104 (Sept. 4, 1945). 



" P. A. Levene and E. P. Clark, /. Biol. Chem. 46, 19 (1921). 

 92 P. A. Levene, J. Biol. Chem. 108, 419 (1935). 

 " F. P. Phelps, U. S. Pat. 2,152,662 (April 4, 1939). 



9* F. J. Bates and associates, "Polarimetry, Saccharimetry and the Sugars," Natl. 

 Bur. Standards (U.S.) Circ. C440, 476 (1942). 



