CHEMISTRY OF RIBOSE AND DEOXYRIBOSE 47 



anhydride was prepared which hydrolyzed to 2,3-di-O-methyl-D-ribose. 

 Oxidation of the anhydride with sodium metaperiodate was also investi- 

 gated, and all the evidence was consistent with the structure of the com- 

 pound being most probably 1 ,5'-5, 1'-diribofuranose anhydride (XLIII). 

 As already briefly mentioned, acetonation of ribose in the presence of 

 sulfuric acid and acetic anhydride leads to the production of a small 

 amount of a product assumed to be 1 ,5-anhydro-2,3-0-isopropylidene-D- 

 ri]>ofuranose. If hydrogen chloride is used as condensing agent, an isomeric 

 compound is obtained having a lower melting point. '°^ Neither compound 

 has been fully investigated. Methyl-2,3-anhydroribosides have been pre- 

 pared by treatment of 2-0-tosyl or 2-0-mesyl derivatives of methyl arab- 

 inoside with sodium methoxide.^''^-"" This anhydro compound has been 

 used as an intermediate in attempted syntheses of 2-deoxyribose as de- 

 scribed on pages 50-51. Hot aqueous sodium hydroxide solution converts 

 methyl 2,3-anhydro-/3-L-riboside into methyl ^S-L-xyloside (75%) and 

 methyl /3-L-arabinoside (25%).-^^ The synthesis and establishment of 

 structure of 1 ,5-anhydroribitol has already been described'" (p. 45). 

 When D-ribobenzimidazole is heated with zinc chloride and concentrated 

 hydrochloric acid at 180°, anhydrization of the sugar molecule occurs to 

 give 2- ( 1 ' , 4 '-anhydro-D-n6o-tetrahy droxybutyl)ben zimidazole .-^^ 



(/) Other Properties. 



D-Ribose reacts very readily with alkyl- and aryl-thiols in the presence 

 of hydrochloric acid.'- "^ Mention has already been made to the conver- 

 sion of ribose into brom-acetyl (and benzoyl) ribose and to uses of the 

 compounds. (See also Baxter et a/."^.) Various references to the action of 

 oxidizing agents on this pentose have already been rjuoted during the 

 course of this review. In general the reactions seem to proceed as expected. 

 It has been reported^"*" that D-ribonic acid is somewhat unstable at room 

 temperature, as indicated by a lowering of the melting point by several 

 degrees after storage for 24 hours. The acid can be converted into a lac- 

 tone, the amide and esters. The tetra-O-acetate of D-ribonic acid when 

 acted on by phosphorus pentachloride gives D-ribonyl chloride tetra-O- 

 acetate. This latter compound can be converted into /ce/o-D-psicose penta- 

 0-acetate by reaction with diazomethane in ether and subsequent treat- 



"' J. Honeyman, /. Chem. Soc. 1946, 990. 



"0 S. Mukherjee and A. R. Todd, /. Chem. Soc. 1947, 969. 



"1 P. W. Kent, M. Stacey, and L. F. Wiggins, /. Chern. Soc. 1949, 1232; Nature 161, 



21 (1948). 

 "2 R. Allerton and W. G. Overend, /. Chem. Soc. 1951, 1480. 

 2" C. F. Huebner, R. Lohmar, R. J. Dimler, S. Moore, and K. P. Link, /. Biol. Chem. 



159, 503 (1945). 

 2" R. A. Baxter, A. C. McLean, and F. S. Spring, /. Chem. Soc. 1948, 523. 



