454 



D. O. JORDAN 



© 



Q 



Fig. 4. Dimensions of cytidine (Furberg'^^*) 



important result on the structure of nucleic acid will be discussed below (see 

 p. 462). 



Preliminary X-ray investigations have also been carried out by Furberg 

 on uridine (X), adenosine (XI), and guanosine (XII). ^^ From the resem- 

 blance of the cell dimensions of uridine to those of cytidine, it is concluded 

 that the stereochemistry of the two molecules are very similar. The data 

 on adenosine confirm that the glycosidic linkage is at N9 and is of the jS- 

 type. The direction of the N9 — Ci bond connecting the two rings was con- 

 sidered by Hendricks^^ and Astbury" to form an angle with the plane of 

 the purine ring so as to make the purine and D-ribose rings parallel. As 



18 S. Furberg, Acta Chem. Scand. 4, 751 (1950). 



19 S. B. Hendricks, /. Phys. Chem. 45, 65 (1941). 



