3//-l,2-Benzodithiol-3-one 1,1-dioxide

Dioxide. The sulfur-transfer reagent 3//-l,2-benzodithiol-3-one 1,1-dioxide (2, eq 1) is widely used in the preparation of oligonucleoside phosphorothioates, which are especially valuable in the development of therapeutic oligonucleotides against various t)q)es of cancer and infectious diseases in humans. ... 

Sulfurization of //-Phosphonate and //-Phosphonothioate Diesters Using 3i/-l,2-benzodithiol-3-one 1,1-Dioxide. Considering the efficiency with which phosphite triesters are converted to the corresponding phosphorothioate triesters upon reaction with 2, investigations on the use of 3i/-l,2-benzodithiol-3-one 1,1-dioxide in the sulfurization of //-phosphonate and //-phosph-onothioate diesters were undertaken. Conversion of the dinucleoside //-phosphonothioate diester (8) to its dithioated diester (9) is accomplished quantitatively within 30 s when a 0.02 M solution of 2 or 1 in 2% aqueous pyridine is used as a sulfurization reagent. 

Stawinski, J, Thelin, M, and von Stedingk, E (1991) Studies on sulfur-ization of nucleoside H-phosphonate and H-phosphonothioate esters using 3H-l,2-benzodithiol-3-one 1,1-dioxide. Nucleosides Nucleotides 10, 517,518. 

Typically, thiosalicylic acid (6) is heated with S-thiobenzoic acid (7) and concentrated sulfuric acid at 50 °C to afford [ S]-3//-l,2-benzodithiol-3-one in 60% yield. Conversion of [ S]-l to its 1,1-dioxide [ S]-2 is performed according to eq 1. The radiolabeled sulfur-transfer reagent exhibits a specific activity of 91 /tiCiZ/timol and is isolated in 30% yield from 6. ... 

Apart from TETD, Beaucage s reagent (3/7-1,2-benzodithiol-3-one-l,1-dioxide) [74] is used most frequently for sulfurization after coupling of the phosphoramidite. The latter is applied in 0.05 molar solution in anhydrous acetonitrile. Sulfurization proceeds within 0.5 min. 

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