184 



J. BADDILEY 



been synthesized in the following manner: A mixed anhydride of diphenyl 

 phosphate and benzyl hydrogen phosphite reacts with 2',3'-isopropylidene 

 adenosine to give the 5'-benzyl phosphite.-^" This is chlorinated with A''- 

 chlorosuccinimide to the phosphorochloridate,"^ which then reacts with 

 the monosilver salt of riboflavin-5'-phosphate. The benzyl group is lost 

 under the experimental conditions employed and the isopropylidene residue 

 removed by acid hydrolysis. From the resulting mixture pure FAD has 

 been isolated. "- 



-0- 



MeCMe 



I I 



l-CH • CH • CH • CH • CHj • OPH 



OCH,Ph 



-0- 



N K O 



N jC > 



2',3'-Isopropylidene adenosine-5'- 

 benzyl phosphite 



OH OH OH 



MeCMe 

 /\ 

 O OCHjPh 



I 

 •-CH-CH-CH-CH-CHrOPCl 

 I II 



N. .N^ 



NH, -^ 



Me 

 Me 



FAD 



CHj-CH- CH-CH-CHi-OPOsHj 





 Riboflavin-5'-phosphate 



d. Coenzyme A (Co A) 



The coenzyme responsible for the transfer of acetyl groups, Co A, is a 

 derivative of the vitamin pantothenic acid.^^^"^*^ Chemical or enzymic hy- 

 drolysis shows that Co A contains equimolar amounts of pantothenic acid, 

 adenine, pentose, and a sulfur compound^^^ subsequently identified as 

 2-mercaptoethylamine.^" • "^ Three phosphate groups are present.^^^ The 



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