31P NMR study on aminoacylation of 5′-AMP and its analogs

Abstract

The progress of aminoacylation of 5′-AMP with amino acids in the presence of several condensing reagents was monitored by 31P NMR. The resulting products were identified on the basis of their 31P NMR chemical shifts. The aminoacylation of 5′-AMP proceeded completely when DCC was used as a condensing reagent under anhydrous conditions. The synthesis of aminoacyl-adenylate analogs substituted with sulfur and a methylene group for the 5′-phosphoryl oxygen and ribosyl 5′-oxygen atoms, respectively, were also examined under various conditions. The 31P NMR analysis of these reactions revealed that the 5′-thiophosphate analogs (aa-AMPSs) substituted with sulfur for the 5′-phosphoryl oxygen were formed as main products by the condensation of 5′-AMPS and amino acids by use of diphenyl phosphorochloridate as a condensing reagent, while 5′-methylenephosphonate derivatives (aa-AMPCs) were formed quantitatively by use of DCC as a condensing reagent.