The relationship between penta-coordinate phosphorus compounds and biochemistry is briefly reviewed. Some interesting phenomena such as peptide formation, ester formation, ester exchange on phosphorus and N to O migration occur at room temperature when the amino group of amino acid is associated with phosphoryl group. Serine or threonine in conjugate of nucleo-side-amino acid could recognize different nucleobases. N-phosphoryl Histine and Ser-His dipep-tide could cleavage nucleic acid, protein and ester in neutral medium. It is found that the above phenomena all undergo penta-coordinate intermediate of phosphorus atom, which is proposed as the key factor to determine their activities.
The study of the fragmentations of the protonated molecular species [M＋H]^＋ and selected fragment ions allowed proposals for the main fragmentation pathways of the title compound. In order to better understand the fragmentation pathways, the MS3 and MS4 spectra of the title compound were obtained. The main fragmentation pathways occur by the cleavage of the C-CO bonds between N-methylpyrrole and carbonyl groups, CO-NH amide bonds, NH-C bonds between the NH groups and the N-methylpyrrole rings, and N-C bonds in 1,4,7,10-tetraazacyclododecane. Electrospray ionization was proven to be a good method for the structural characterization and identification of this kind of compound.
Nucleases play an important role in molecular biology, for example, in DNA sequencing. Synthetic polyamide conjugates can be considered as a novel tool for the selective inhibition of gene expressions and also as potential drugs in anticancer or antiviral chemotherapy. In this article, the synthesis of a novel minor-groove targeting artificial nuclease, an oligopyrrol-containing compound, has been reported. It was found that this novel compound can bind DNA in AT-rich minor groove with high affinity and site specificity. DNA binding behavior was determined by using UV-Vis and CD. It is indicated that compound 6 can enhance the Tm, of DNA from 80.4 ℃ to 84. 4 ℃ and that it possesses a high binding constant value（Kb =3.05 × 10^4 L/mol）.
Daidzein （7,4＇-dihydroxyisoflavone） was phosphorylated by a modified Atherton-Todd reaction. The structures of the five target product, were determined by X-ray, IR, NMR and ESI-MS. Electrospray ionization results show that in the gas phase all the phosphorylated daidzein derivatives could form non-covalent complexes with the protein lysozyme, while non-covalent complexes were not detected in the mixed solution of daidzein with lysozyme. Relative affinity of every non-covalent complex was obtained according to its different decomposition orifice voltage.
