172 



J. BADDILEY 



tides are dephosphorylated by a 5'-nucleotidase/^* and they behave in the 

 manner expected for 5'-phosphates on ion-exchange columns. '^^ [Cf. Cohn, 

 Chapter 6.] 



The thymidine nucleotide has been shown to possess the structure thy- 

 midine-5'-phosphate (XXXVII) by synthesis^^^ (see p. 175). 



OH 

 I 

 •-CH-CHi-CH-CH-CHi-OPOsHa 



I 



-0- 



nJC > 



NH, 



XXXVI 



Adenine deoxyriboside-5'-phosphate 



OH 

 I 

 ■-CH-CHs-CH-CH-CHs-OPOjHj 



N^Me 

 OH 



XXXVII 



Thymidine-S'-phosphate 



I. Deoxynucleoside Diphosphates 



Acid hydrolysis of deoxyribonucleic acid gives, in addition to pyrimidine 

 deoxyriboside phosphates, varying amounts of diphosphates of thymidine 

 and cytosine deoxyriboside.^*""^^^ Chromatographic evidence also suggests 

 the presence in the hydrolysate of traces of the diphosphate of 5-methyl- 

 cytosine deoxyriboside."* Catalytic hydrogenation of thymidine diphos- 

 phate, followed by mild acid hydrolysis, gives dihydrothymidine and a 

 reducing sugar diphosphate. These diphosphates are the 3' , 5'-diphosphates 

 of thymidine (XXXVIII) and cytosine deoxyriboside (XXXIX) as is 

 shown by their synthesis from thymidine and cytosine deoxyriboside by 

 direct phosphorylation."* 



-0 



PO3H2 







l-CH-CH.-CH-CH-CHiOPOaHj 



N^Me 

 OH 



XXXVIII 



Thymidine-3', 5'- diphosphate 



-0- 



PO3H2 







I I 

 L-CH-CHrCH-CH-CHj OPO3H2 



0=< 1 



NH2 



XXXIX 



Cytosine deoxynbosidehS' ,5'- diphosphate 



3. Synthesis of Nucleotides 



The formulas assigned to the nucleotides are supported, in some cases, 

 by synthesis. At the present time unambiguous syntheses exist for the 



•" C. E. Carter, J. Am. Chem. Soc. 73, 1537 (1951). 



136 E. Volkin, J. X. Khym, and W. E. Cohn, J. Am. Chem. Soc. 73, 1535 (1951). 



1" A. M. Michelson and A. R. Todd, J. Chem. Soc. 1953, 951. 



