94] Preparation of nucleotides and derivatives

Abstract

Publisher Summary This chapter discusses the preparation of nucleotides and derivatives. The preparations of simpler mononucleotides and derivatives include those of the p -nitrophenyl esters of thymidine 3′-phosphate and thymidine 5′-phosphate, ribonucleoside cyclic 2′,3′-phosphates, and ribonucleoside cyclic 3′,5′-phosphates. 8-Cyanoethyl phosphate on activation with dicyclohexylcarbodiimide gives a new and exceedingly powerful phosphorylating agent. Finely powdered anhydrous sodium p -nitrophenoxide is added slowly with stirring to phosphorus oxychloride contained in a flask equipped with a reflux condenser and cooled in an ice-salt bath. A solution of 5′- O -tritylthymidine in anhydrous dioxane is added dropwise, with exclusion of moisture, to a magnetically stirred solution of p-nitrophenyl phosphorodichloridate in anhydrous dioxane and dry pyridine. Thymidine 5′-phosphate is esterified with p -nitrophenol on treatment with dicyclohexylcarbodiimide in the presence of triethylamine. The p -nitrophenyl ester is isolated as its sodium salt in 70% yield after partition chromatography on cellulose. The ribonucleoside 2′ (3′)-phosphate is reacted with dicyclohexylcarbodiimide in the presence of triethylamine. The resultant cyclic phosphate is isolated as its anhydrous calcium salt.