2080-58-2Relevant academic research and scientific papers
Synthesis of phosphorodithioate DNA via sulfur-linked, base-labile protecting groups
Wiesler,Caruthers
, p. 4272 - 4281 (2007/10/03)
Phosphorodithioate DNA, a new and potentially useful DNA analog with a deoxynucleoside-OPS2O-deoxynucleoside internucleotide linkage, was synthesized from deoxynucleoside 3'-phosphorothioamidites having a variety of thioesters and thiocarbonates as base-labile phosphorus protecting groups. The major challenge in the synthesis of this DNA analog was to derive a reaction pathway whereby activation of deoxynucleoside 3'-phosphorothioamidites occurred rapidly and in high yield under conditions that minimize Arbuzov rearrangements, exchange reactions, unwanted oxidation to phosphorothioates, and several other side reactions. Of the various phosphorus protecting groups examined for this purpose, a thorough evaluation of these parameters led to the conclusion that β-(benzoylmercapto)ethyl was preferred. Synthesis of phosphorodithioate DNA began by preparing deoxynucleoside 3'-phosphorothioamidites from the appropriately protected deoxynucleoside, tris(pyrrolidino)phosphine, and ethanedithiol monobenzoate via a one-flask synthesis procedure. These synthons were activated with tetrazole and condensed with a deoxynucleoside on a polymer support to yield the deoxynucleoside thiophosphite. Subsequent steps involved oxidation with sulfur to generate the completely protected phosphorodithioate triester, acylation of unreacted deoxynucleoside, and removal of the 5'-protecting group. Yields per cycle were usually 97-98% with 2-5% phosphorothioate contamination as determined by 31P NMR. By using deoxynucleoside 3'-phosphorothioamidites and deoxynucleoside 3'-phosphoroamidites, deoxyoligonucleotides having phosphorodithioate and the natural phosphate internucleotide linkages in any predetermined order can also be synthesized.
Convenient procedure for converting 1,3-dithiolane-2-thiones into 1,3-dithiolan-2-ones
Barbero, Margherita,Degani, Iacopo,Dughera, Stefano,Fochi, Rita,Piscopo, Laura
, p. 289 - 294 (2007/10/03)
1,3-Dithiolan-2-ones have been obtained by reaction of 1,3-dithiolane-2-thiones and epoxides in the presence of HBF4·Et2O. The reactions, carried out in anhydrous CH2Cl2 at 0-5°C→room temperature (Procedure A) or in anhydrous chlorobenzene at 0-5→80°C (Procedure B), gave product yields of 63-95%. By Procedure B it was also possible to isolate the intermediates 1-oxa-4,6,9-trithiaspiro[4,4]nonanes in good yields (66-85%). Reaction pathways are proposed.
The Preparation of Cyclic Dithia and Thiaza Compounds by the Reaction of Potassium Carbonate with Heterocumulenes and Alkylene Dibromides or Carbonate Catalyzed by Organostannyl Compounds
Fujinami, Tatsuo,Sato, Shinichi,Uchida, Norimasa,Sakai, Shizuyoshi
, p. 1174 - 1177 (2007/10/02)
Cyclic 1,3-dithia- and 1,3-thiaza-2-ylidene compounds were obtained by the heterogenous reaction of solid potassium carbonate, a sulfur-containing heterocumulene, such as aryl isothiocyanate, carbon disulfide, or carbonyl silfide, and alkylene dibromides or ethylene carbonate in the presence of bis(tributylstannyl) compounds.The effect of an organostannyl catalyst on these reactions is discussed.
HOMOLYTIC LIQUID-PHASE TRANSFORMATIONS OF 2-ETHOXY-1,3-DITHIOLANE AND 2-ETHOXY-1,3-OXATHIOLANE
Batyrbaev, N. A.,Zorin, V. V.,Zlotskii, S. S.,Rakhmankulov, D. L.
, p. 1369 - 1371 (2007/10/02)
The direction of the homolytic transformations in 2-ethoxy-1,3-dithiolane and 2-ethoxy-1,3-oxathiolane was investigated. 1,3-Dithiolane and 1,3-dithiolan-2-one are formed from 2-ethoxy-1,3-dithiolane, and 1,3-oxathiolane-2-one, 1,3-oxathiolane, ethyl thioformate, and diethyl monothiocarbonate are formed from 2-ethoxy-1,3-oxathiolane.The temperature dependence of the yield and ratio of the reaction products was determined.
