Characteristic fragmentation behavior of the analogs of endomorphin-2 with phenylglycine in position 3 or 4 by ESI-FT tandem mass spectrometry

A series of analogs of endomorphin-2 （EM-2） with phenylglycine （Phg） in position 3 or 4 were synthesized. In electrospray ionization Fourier transform ion cyclotron resonance （ESI-Fr-ICR） MS/MS spectra of these compounds, some b, y, a, and internal ions were observed and slight mass differences between the calculated and observed results are obtained. Their sequences were derived successfully. However, the MS/MS patterns of these analogs with Dphg and Lphg were very similar. It is hard to distinguish them by MS/MS spectra. Moreover, if the third position was substituted by phenylglycine （L or D）, a rearrangement could occur in MS/MS experiment to lose proline residue.

Fabrication and adsorption property of novel adsorbent for potential application to wastewater with Fe(Ⅲ) ions

The spherical macroporous cellulose(SMC) was fabricated using medical absorbent cotton as raw material and nano CaCO3 as porogenic agents.And then,the phenylglycine was grafted onto the SMC to obtain the novel spherical macroporous cellulose derivative adsorbent(PSMC).FT-IR and scanning electron microscope(SEM) were employed to characterize the adsorbents and Fe3+ ions served as model solute to evaluate the adsorption property of the adsorbents.The experimental results show that the amount of porogenic agents and the value of pH have obvious influence on adsorption capacity of the adsorbents.The data of adsorption kinetic and isotherm display that the adsorbents possess excellent equilibrium adsorption capacity(348.94 mg/g) and have a bright prospect and considerable potential in the treatment of Fe3+ ions in wastewater.

A Concise,Practical Chiral Resolution Approach of Racemic (E)-4,4-Dimethyl-1-(4-nitrophenyl) pent-1-en-3-ol to Its both Enantiomers via Strategy of Diastereomeric Ester Formation and Crystallization Using both N-Boc-D- and N-Boc-L-phenylglycines as Chiral Auxiliaries

Chiral secondary alcohols are an important class of functionalities commonly seen in drugs and other bioactive compounds.In an ongoing drug discovery program in our laboratories,a nitro-bearing racemic allylic secondary alcohol (±)-1 was discovered as a promising drug candidate,and in the following preclinical studies,a concise,reliable,practical synthetic approach to its both enantiomers with high optical purities was greatly needed.In the present study,we developed a chiral resolution approach of (±)-1 to its both enantiomers,i.e.,(+)-1 and (-)-1,via the strategy of diastereomeric ester formation and crystallization using both N-Boc-D- and N-Boc-L-phenylglycines as chiral auxiliaries.The absolute configurations of all the four key intermediates were unambiguously determined by single-crystal X-ray diffraction,providing a solid foundation for the stereochemistry of the present study.The two enantiomers were obtained in high optical purities.This approach is characterized by scalability and practicality and is envisaged to enable the chiral resolution of other racemic secondary alcohols,especially those with labile groups,such as NO_(2);olefinic C=C bond.

Application of modified amino acid as a chiral building block in asymmetric synthesis

Phenylglycine 1 as a representative of natural resourceful a-amino acid was modified by reduction and protection of functional group to afford the amino alcohol as a chiral building block 3. A new chiral compound, the chiral building block/spiro-cyclopropane derivative containing four stereogenic centers, compound 7, has been obtained in 52% yield with de≥98% via the tandem double Michael addition/internal nucleophilic substitution under mild condition of 5-l-menthyloxy-3-bromo-2-(5H)-furanone 4 with the nucleophilic reagent, the amino alcohol 3. The new chiral compound 7 is identified on the basis of its analytical data and spectroscopic data, such as UV, IR, 1H NMR, 13C NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes 7 was established by X-ray crystallography. This result can provide new route and method for the introduction of chiral building block and the important synthetic strategy in synthesis of some complex molecules containing