Abstract
Reaction ofDl-serine and adenosine-5-phosphorimidazolide in the presence of adenosine-5′-(O-methylphosphate) and imidazole resulted in the stereoselective synthesis of the aminoacyl nucleotide ester 2′(3′)-O-seryl-adenosine-5′-(O-methylphosphate). The enantiomeric excess ofd-serine incorporated into 2′(3′)-O-seryl-adenosine-5′-(O-methylphosphate) was about 9%. Adenylyl-(5′→N)-serine and an unknown product also incorporated an excess ofd-serine; however, serylserine showed an excess ofl-serine. The relationship of these results to the origin of the biological pairing ofl-amino acids and nucleotides containingd-ribose is discussed.