O2AIBN, free-radical method for the stereospecific oxidation of nucleoside trialkyl phosphites: new preparation of the individual, diastereomeric, 18O-labeled thymidine 3′, 5′-cyclic monophosphates.
✍ Scribed by Tadeusz M. Gaida; Alan E. Sopchik; Wesley G. Bentrude
- Publisher
- Elsevier Science
- Year
- 1981
- Tongue
- French
- Weight
- 233 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
An experimentally easy method for reqio-and stereospecific introduction of isotopic (I80 or 170) oxyqen into phosphorus di-and triesters of bioloqical interest is described and applied to 'DO-labelinq of cTMP's. Nucleoside 3',5'-cyclic monophosphates stereospecifically labeled with I80 or I70 in the exocyclic oxyqen atoms attached to phosphorusI are most valuable substrates for the study of enzyme catalyzed reactions of cyclic nucleotides as shown by recent stereochemical investiqations.? We report here a new method for the preparation of the diastereomerically pure '*D-labeled 3',5'-cyclic monophosphates of thymidine (cTMP's), IVa and IVb, via a freeradical chain process usinq 180 2. The approach has the advantaqes of beinq simple and straiqhtforward and also utilizinq the oxyqen isotope in its most economical form. Furthermore, the hiqh stereo-and reqiospecificities of the introduction of laheled oxyqen and lack of side products suqqest its application to the oxidation and IDO lahelinq of the trialkyl phosphite intermediates frequently used in oliqonucleotide svnthesis. 3