Synthesis of 8-bromo- and 8-azido-2'-deoxyadenosine-5'-O-(1-thiotriphosphate)

Abstract Treatment of 3′-O-methoxyacetylated 8-bromo-2′-deoxyadenosine (5), with a twofold excess of salicyl phosphorochloridite (6), and subsequent reaction with bis(tri-n-butylammonium) pyrophosphate and oxidation with sulfur followed by removal of the protecting group gives predominantly 8-bromo-2′-deoxyadenosine-5′-O-(1-thiotriphosphate) (7), and minor amounts of the corresponding brominated monothiophosphate. Alternatively, the photoreactive dATP analog 8-azido-2′-deoxyadenosine-5′-O-(1-thiotriphosphate) (11), is obtained by phosphorylation of unprotected 8-azido-2′-deoxyadenosine (9) with a 1.8 molar equivalent excess of thiophosphoryl chloride and bis(tri-n-butylammonium) pyrophosphate. A protection of the nucleobase 6-amino group is not required. The photoaffinity labeling reagent 11, was characterized by 31P-NMR and ion-spray mass spectroscopy and its photolysis upon long wavelength UV irradiation was studied. Both α-thioderivatives of 2′-deoxyadenosine triphosphates can be incorporated into plas...