32 



W. G. OVEREND AND M. STAGEY 



H— C 



H— C— OH 

 H— C— OH 



H— C— O — 



I 

 CH2OH 



XXXI 



CH3 



CH3 



NH, 



NO2 



XXXII 



CHO 

 H— C— OH 

 + H— C— OH 

 H— C— OH 

 CHiOTr 



XXXIII 



\ 



\ 



H— C 



H— C— OH 

 H— C— OH 



H— C— O— J 



I 

 CHjOTr 



-NH- 



CH3 

 — CH3 



NO5 



XXXIV 



Subsequently Folkers and co-workers^ ^^ prepared 5 , 6-dimethylbenzimi- 

 dazole-a- and -j3-D-ribopyranoside. The /3-pyranoside (XXXV) has also 

 been synthesized by Petrow et a/.^** The pyranose structure was confirmed 

 by periodate titration and the /S-configuration of the sugar-base linkage was 

 assumed from the method of synthesis, i.e., that 5 ,6-dimethylbenzimidazole 

 silver and a-acetobromoribose react with concomitant Walden inversion 

 to give the acetate of XXXV, which would thus have a j8-linkage. 



XXXV 



'«6F. W. Holly, C. H. Shunk, Elizabeth W. Peel, J. J. Cahill, J. B. Lavigne, and 



K. Folkers, /. Am. Chem. Soc. 74, 4521 (1952). 

 '«8 G. Cooley, B. Ellis, P. Mamalis, V. Petrow, and B. Sturgeon, J. Phann. and 



Pharmacol. 2, 579 (1950). 



