180 



J. BADDILEY 



In the synthesis of ADPi^^ adenosine-5'-benzyl phosphate is obtained by 

 simultaneous removal in acid of one benzyl and the isopropylidene residue 

 from 2',3'-isopropylidene adenosine-5'-dibenzyl phosphate (formula, p. 

 173). The silver salt of this monobenzyl ester, with dibenzyl phosphoro- 

 chloridate, gives adenosine-5'-tribenzyl pyrophosphate. Catalytic hydro- 

 genation of this gives ADP. 



-0- 



OH OH 



OCH^Ph 



f 



N 



N, 



NH, 



"-CH-CH-CH-CH-CH.-O-P-OH 



I II 



N 



-0- 



ADP 



-, /Hs/Pd 



OH OH PhCH,0 OCHjPh 



II II 



l-CH-CH-CH-CH-CH^-O-P-O-P-OCH^Ph 



I II II 



N. 



NH, 



T N 



Adenosine-5'-tnbenzyl pyropnosphate 



-0- 



OH OH 



f 



N, 



NH, 



CH 



I 



N. 



PhCH^O OCHjPh 



CH-CH-CH-CHj-O-P-O-P-OHl 



II II 

 



-0 



ATP 



'Hj/Pd 



OH OH 



OCHjPh 



I OCHjPh 



f 



N, 



PhCH.O 

 I 

 ^CH-CH-CH-CH-CHrO-P-O-P-O-P-OCHsPh 



I II II II 



N. 



T N 



NHs 



When adenosine-5'-tribenzyl pyrophosphate is heated with a teritary 

 base-'^ one benzyl group is lost. The resulting dibenzyl ester, as its silver 

 salt, is phosphorylated wdth a further mol. of dibenzyl phosphorochloridate 

 giving a tetrabenzyl ester of ATP, from which benzyl groups may be re- 

 moved readily by catalytic hydrogenation.^^o -pj^g synthesis has been simpli- 

 fied by direct phosphorylation of the disilver salt of adenosine-5'-phosphate 

 with 2 mol. dibenzyl phosphorochloridate, and then removal of benzyl 

 groups as before. An unstable cyclic intermediate is thought to be formed in 

 this synthesis.^-^ 



"0 J. Baddiley, A. M. IVIichelson, and A. R. Todd, /. Chem. Soc. 1949, 582. 

 "1 A. M. Michelson and A. R. Todd, J. Chem. Soc. 1949, 2487. 



