title: Identification of amino acid phosphorodiamidates of antiviral nucleosides using electrospray ionization tandem mass spectrometry.
abstract: Several amino acid phosphorodiamidate derivatives of d4T as anti-HIV prodrugs were synthesized and investigated using electrospray ionization multistage tandem mass spectrometry (ESI-MS(n)). A novel methyl group migration in gas phase was observed in ESI-MS(2) of the sodium adducts of amino acid methyl ester of phosphorodiamidates of 2',3'-didehydro-2',3'-dideoxythymidine (d4T). The proposed structures of the rearrangement ions were confirmed by high resolution tandem mass spectrometry. A possible mechanism involving the pentacoordinate phosphoric-carboxylic phosphate anhydride was proposed, in which a seven-membered ring intermediate was formed by coordination with the metal ion between the phosphoryl group and carbonyl oxygen atom. Thus, the intrinsic properties of phosphoryl group might be the key factors responsible for this migration.
authors: Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
authors: Juntao
authors: J
authors: Cui
authors: Xiang
authors: X
authors: Gao
authors: Aiting
authors: A
authors: Fan
authors: Shuangyan
authors: S
authors: Zhang
authors: Yan
authors: Y
authors: Liu
authors: Pengxiang
authors: P
authors: Xu
authors: Yufen
authors: Y
authors: Zhao
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D019380:Anti-HIV Agents / Q000737:chemistry; D017553:Phosphorus Compounds / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D018119:Stavudine / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D015215:Zidovudine / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D019380:Anti-HIV Agents; D017553:Phosphorus Compounds; D015215:Zidovudine; D018119:Stavudine; C436301:phosphorodiamidic acid