CHEMICAL BONDS IN NUCLEIC ACIDS 



415 



are readily hydrolyzed to a mixture of the nucleoside-2'- and nucleoside-3'- 

 phosphates. The free isomeric mononucleotides are, like the glycerol mono- 

 phosphates, stable without interconversion in alkaline solution. 



Ila^ 



R-CH 



CH,-OH ^ 



lib 



2. Esters of the Mononucleotides 



Bailly and Gaume^^ showed that whereas glycerol-a-phosphate is stable 

 to alkali, glycerol-a methyl hydrogen phosphate (IV; R = Me) is readily 

 hydrolyzed under alkaline conditions to methanol and a mixture of glycerol- 

 a- and -iS-phosphate ; no methyl phosphate is produced. Similar observations 

 by Baer and Kates^^ show that the choline phosphate (IV; R = choline 

 residue) is hydrolyzed to choline and glycerol-a- and -/3-phosphate, while 

 alkaline degradation of the lecithins also results in phosphoryl migration." 

 2-Hydroxyethyl dimethyl phosphate (V) under the action of dilute alkali 

 yields 2-hydroxyethyl phosphate (VI) with loss of methanol. ^^ Mild acid 

 treatment also effects these degradations. It is noteworthy, however, that 

 2-methoxyethyl dimethyl phosphate (VII) forms 2-methoxy ethyl methyl 

 hydrogen phosphate (VIII) with alkali, and this is now stable to further 

 hydrolysis, a result which is in accord with the generally recognized stability 

 of dialkyl esters of phosphoric acid towards alkaline reagents.^*"®' 



OH 



I 

 H0-CH2-CH-CH,-0P0(0H)-OR 



IV 



HO-CH2-CH2-OPO(OMe)2 

 V 



OR 



W/ 

 P 



I I 



HO-CH^-CH-CHz 

 IX 



HO-CHj-CH^-OPOaH^ 

 VI 



OH 



W/ 



p 



-*H0-CH,-CH-CH, 

 X 



Me0-CH2-CH.2-0P0(0Me) 

 VII 



Me0-CH2-CH2-0P0(0H)-0Me 

 VIII 



" O. Bailly and J. Gaurn^, Bull. soc. chim. 2, 354 (1935). 

 ^6 E. Baer and M. Kates, J. Biol. Chem. 175, 79 (1948). 

 " E. Baer and M. Kates, J. Biol. Chem. 185, 615 (1950). 

 ^8 O. Bailly and J. Gaum^, Bull. soc. chim. 3, 1396 (1936). 

 "J. Cavalier, Compt. rend. 127, 114 (1898). 



