title: An approach to the stereoselective synthesis of Sp-dinucleoside phosphorothioates using phosphotriester chemistry.
abstract: An approach to the stereoselective synthesis of Sp- dinucleoside phosphorothioates has been investigated which utilizes phosphotriester chemistry. The stereoselectivity of internucleotide bond formation between N4-benzoyl-5'-O-(4,4'-dimethoxytrityl)-2'-deoxycytidine-3'-O-(S2-cyano-e thyl) phosphorothioate (3) and 3'-O-acetylthymidine has been studied using either mesitylenesulphonyl-5-(pyridin-2-yl)tetrazole (MSPy) or 1-mesitylenesulphonyl-3-nitro-1,2,4-triazole (MSNT) as the activating agent. The removal of the cyanoethyl group from the protected dinucleoside phosphorothioate has been studied, and conditions are reported which provide rapid deprotection without concomittant desulphurisation.
mesh_terms: D001555:Benzene Derivatives; D002855:Chromatography, Thin Layer; D015226:Dinucleoside Phosphates; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000032:analysis / Q000138:chemical synthesis* / Q000302:isolation & purification; D010755:Organophosphates; D013237:Stereoisomerism
chemical_list: D001555:Benzene Derivatives; D015226:Dinucleoside Phosphates; D009841:Oligonucleotides; D010755:Organophosphates; C010219:mesitylene