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ABSTRACT: The mass spectral behavior of amino acid methyl ester phosphoramidate derivatives have been investigated using electrospray ionization multistage mass spectrometry (ESI-MS(n)) and moderate theoretical calculations at the B3LYP/6-31G(d) level. A novel methyl group migration to the phosphoryl group with the formation of the intermediate cyclic aminoacylphosphoramidate was found. 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 the metal ion coordination with the phosphoryl and carbonyl groups and the intrinsic properties of phosphoryl group might be the key factors responsible for this novel migration.
Rapid Communications in Mass Spectrometry 04/2011; 25(8):1061-9. · 2.79 Impact Factor
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ABSTRACT: The nucleoside-based antiviral phosphoramidates and H-phosphonates were synthesized and separated using reversed-phase liquid chromatography on bridged ethane hybrid (BEH) C₁₈ column packed with 1.7 μm particles of non-chiral stationary phase. The influences of the composition of mobile phase and column temperature have been investigated to optimize the diastereoisomeric separation. Complete separations of the phosphoramidate and H-phosphonate prodrugs with good resolution (R(S)=1.99-2.77) were achieved within a short time (5-9 min). The validation study of the optimized method including linearity, accuracy, repeatability and detection limit has revealed it is better performance versus conventional HPLC method. In addition, HPLC was combined with high resolution electrospray ionization time-of-flight mass spectrometry (ESI-TOF MS), which enabled the exact mass measurement and high sensitivity. Using MS as detection, the limits of detection and limits of quantification of the studied pronucleotide diastereoisomers were determined in the range of several nmol L⁻¹ level.
Journal of chromatography. A 03/2011; 1218(10):1416-22. · 4.19 Impact Factor
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ABSTRACT: Amino acid homochirality, as a unique behavior of life, could have originated synchronously with the genetic code. In this paper, phosphoryl amino-acid-5'-nucleosides with P-N bond are postulated to be a chiral origin model in prebiotic molecular evolution. The enthalpy change in the intramolecular interaction between the nucleotide base and the amino-acid side-chain determines the stability of the particular complex, resulting in a preferred conformation associated with the chirality of amino acids. Based on the theoretical model, our experiments and calculations show that the chiral selection of the earliest amino acids for L-enantiomers seems to be a strict stereochemical/physicochemical determinism. As other amino acids developed biosynthetically from the earliest amino acids, we infer that the chirality of the later amino acids was inherited from the precursor amino acids. This idea probably goes far back in history, but it is hoped that it will be a guide for further experiments in this area.
Science in China Series C Life Sciences 11/2007; 50(5):580-6. · 1.61 Impact Factor
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ABSTRACT: This article describes the synthesis of -hydroxyphosphonic acid esters using the Pudovik reaction. IR, 1H NMR, 13C NMR, 31P NMR, MS, and elemental analysis were employed to confirm their structures. X-ray structure analysis is reported for six compounds. The antibacterial activities of these compounds are also reported. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Scientific Research Foundation of Third Institute of Oceanography, SOA [2009005]; National Natural Science Foundation of China [40806032, 20732004]; Natural Science Foundation of Fujian Province of China [2009J05099]
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Fang,
Hua（State Ocean Adm,
Inst Oceanog,
Wang,
Dongdong（Xiamen Univ,
Dept Pharmaceut Sci）,
Coll Med）, Weizhu Chen,
Yufen Zhao,
赵玉芬,
Meijuan（ Xiamen Univ
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ABSTRACT: Some novel arylcarboxy esters of alpha-hydroxyphosphonate were synthesized via the reaction of a-hydroxyphosphonate with benzoic acid chloride or isonicotinic acid chloride. Their structures were confirmed by elemental analysis, IR, H-1 NMR, C-13 NMR, P-31 NMR and mass spectra. The crystal structure of compound Cl was determined by X-ray diffractometer. The sodiated adduct of the title compounds appeared a novel rearrangement reaction by positive ion electrospray ionization mass spectrometry in conjunction with tandem mass spectrometry. A possible rearrangement mechanism was proposed.
