99388-22-4

Upstream product

• 65452-14-4 dansyl-D,L-leucine 
• 328-38-1 (R)-leucine 
• 605-65-2 5-(dimethylamino)naphth-1-ylsulfonyl chloride 

Relevant academic research and scientific papers

Fluorescent cyclodextrins for molecule sensing: Fluorescent properties, NMR characterization, and inclusion phenomena of N-dansylleucine-modified cyclodextrins

Fluorophore-amino acid-cyclodextrin (CD) triad systems, N-dansyl-L-leucine-modified and N-dansyl-D-leucine-modified β-CD (1, 2) and N-dansyl-L-leucine-modified and N-dansyl-D-leucine-modified γ-CD (3, 4), were synthesized and characterized as fluorescent indicators of molecular recognition. Fluorescence decay analyses of these CD derivatives indicated that there exist two lifetime components, being in equilibrium with each other in aqueous solution, with the dansyl moiety included in its own cavity (self-inclusion) for the larger lifetime component while located outside the cavity for the shorter lifetime one. The structural analyses of β-CD derivatives 1 and 2 undertaken by combined use of 1D and 2D NMR spectra indicate that the dansyl moiety of 2 is more deeply included in the CD cavity than that of 1. The leucine residue between the dansyl and the CD moieties of these hosts was more effective in enhancing the binding abilities for various guests when compared with the glycine residue of the corresponding hosts. The difference in the enantiomeric configuration of the leucine residue caused the difference in the binding constants with larger values for 1 than 2 and with the opposite trend for the γ-CD derivatives 3 and 4. Upon guest addition, the fluorescence intensities of 1 and 2 decreased, reflecting the exclusion of the dansyl moiety from inside to outside of the β-CD cavity, while the fluorescence intensities of the γ-CD derivatives 3 and 4 depended on the guest as shown by the increase induced by cyclohexanol and the decrease by (-)-borneol and other larger guests. These guest-responsive variations of the fluorescence intensity enabled these hosts to be used as effective fluorescent indicators of molecular recognition.

NMR Studies of Conformations of N-Dansyl-L-leucine-Appended and N-Dansyl-D-leucine-Appended β-Cyclodextrin as Fluorescent Indicators for Molecular Recognition

The structures of N-dansyl-L-leucine-appended β-cyclodextrin (1) and N-dansyl-D-leucine-appended β-cyclodextrin (2) were estimated by the combined use of 1D and 2D NMR techniques (1D and 2D TOCSY, ROESY, PFG MQF-COSY, PFG HSQC, and NOE difference spectra). The dansyl moiety of 2 is included in its own cavity more deeply than that of 1. The difference in the properties between 1 and 2 was interpreted by the difference in the inclusion depth of the dansyl moieties. Their conformational changes upon addition of 1-adamantanol were also studied by NMR. The chemical shifts and patterns of 1H resonances for the protons of the dansyl, leucine, and cyclodextrin parts were changed upon addition of the guest. These changes indicated the exclusion of the dansyl moiety from the cyclodextrin cavity to bulk water upon addition of the guest.

Preparation and evaluation of a triazole-bridged bis(β-cyclodextrin)–bonded chiral stationary phase for HPLC

A triazole-bridged bis(β-cyclodextrin) was synthesized via a high-yield Click Chemistry reaction between 6-azido-β-cyclodextrin and 6-propynylamino-β-cyclodextrin, and then it was bonded onto ordered silica gel SBA-15 to obtain a novel triazole-bridged bis (β-cyclodextrin)–bonded chiral stationary phase (TBCDP). The structures of the bridged cyclodextrin and TBCDP were characterized by the infrared spectroscopy, mass spectrometry, elemental analysis, and thermogravimetric analysis. The chiral performance of TBCDP was evaluated by using chiral pesticides and drugs as probes including triazoles, flavanones, dansyl amino acids and β-blockers. Some effects of the composition in mobile phase and pH value on the enantioseparations were investigated in different modes. The nine triazoles, eight flavanones, and eight dansyl amino acids were successfully resolved on TBCDP under the reversed phase with the resolutions of hexaconazole, 2′-hydroxyflavanone, and dansyl-DL-tyrosine, which were 2.49, 5.40, and 3.25 within 30 minutes, respectively. The ten β-blockers were also separated under the polar organic mode with the resolution of arotinolol reached 1.71. Some related separation mechanisms were discussed preliminary. Compared with the native cyclodextrin stationary phase (CDSP), TBCDP has higher enantioselectivity to separate more analytes, which benefited from the synergistic inclusion ability of the two adjacent cavities and bridging linker of TBCDP, thereby enabling it a promising prospect in chiral drugs and food analysis.

Cationic β-cyclodextrin-modified hybrid magnetic microspheres as chiral selectors for selective chiral absorption of dansyl amino acids

Chirally selective functionalized magnetic microspheres show great potential in enantiomeric separations. In this study, a novel class of chiral magnetic selectors was developed by immobilization of vinylimidazolium-β- cyclodextrin chloride (VIMCD-Cl) on 3-methacryloxypropyltrimethoxysilane- modified iron oxide magnetic microspheres through a radical polymerization. The prepared chiral materials have regular three-dimensional core-shell architectures with an average particle size of about 580 nm and a high magnetization saturation of about 51 emu g-1. Fourier transform-infrared spectra (FT-IR), thermogravimetric analysis (TGA) and elemental analysis confirmed that VIMCD-Cl was successfully polymerized on the surface of the magnetic microspheres. The prepared functional magnetic materials were then applied in the selective chiral absorption of three dansyl amino acids using microbatch technology. The results indicated that VIMCD-Cl immobilized magnetic microspheres (VIMCD-MNPs) possessed good enantioselectivities toward the three dansyl amino acids, and showed stronger interactions with the l-enantiomers during the chiral adsorption process. Furthermore, these functionalized chiral magnetic materials possess an excellent recyclability and can be used as effective chiral magnetic selectors for chiral separations.

Chiral separation of enantiomers of amino acid derivatives by HPLC on vancomycin and teicoplanin chiral stationary phases

The chiral separation of α-amino acids by liquid chromatography using macrocyclic antibiotic bonded stationary phases were studied. Teicoplanin and vancomycin bonded stationary phases have been used to separate enantiomers of dansyl amino acids in the reversed - phase high performance liquid chromatography mode. By comparison of chromatographic parameters obtained by use of both chiral stationary phases it the mechanism of chiral separation could be suggested. The better separation - greater value of R(j,i) of enantiomers - was achieved by the teicoplanin column.

Direct resolution of optically active isomers on chiral packings containing ergoline skeletons. 5. Enantioseparation of amino acid derivatives

A new procedure for ergot alkaloid-based chiral stationary phase preparation is described. Synthesis is based on bonding the allyl derivative of terguride to mercaptopropylsilanized silica gel. The packing exhibits higher content of chiral selector, stability, reproducibility, and enantioselectivity toward amino acids compared to that previously studied. The chromatographic behavior of amino acids with different side chains and substituent groups is investigated in order to obtain a deeper insight into the enantiodiscriminative mechanism as well as to determine the limitations and strengths of terguride as a chiral selector for this class of compounds. A variety of factors, including mobile phase parameters such as pH, ionic strength, content and nature of organic modifier, and temperature, are examined. A new procedure for ergot alkaloid-based chiral stationary phase preparation is described. Synthesis is based on bonding the allyl derivative of terguride to mercaptopropylsilanized silica gel. The packing exhibits higher content of chiral selector, stability, reproducibility, and enantioselectivity toward amino acids compared to that previously studied. The chromatographic behavior of amino acids with different side chains and substituent groups is investigated in order to obtain a deeper insight into the enantiodiscriminative mechanism as well as to determine the limitations and strengths of terguride as a chiral selector for this class of compounds. A variety of factors, including mobile phase parameters such as pH, ionic strength, content and nature of organic modifier, and temperature, are examined.

Marine natural products. XXV. Biologically active tridecapeptide lactones from the Okinawan marine sponge Theonella swinhoei (theonellidae). Structure of theonellapeptolide Id

Theonellapeptolide Id (1), a tridecapeptide lactone, was isolated from the Okinawan marine sponge Theonella swinhoei and the structure 1 was determined. A new HPLC analysis method for analyzing the amino acid composition of 1 containing N-methyl amino acids was devised.