Search results for "SoMe"

Endor Determined Structure and Conformation of Spin-Labeled Methyl L-Phenylalanate in Frozen Solutions

1990

The conformation of L-phenylalanine and methyl L-phenylalanate acylated at the amino nitrogen position with the nitroxyl spin-label 2,2,5,5-tetramethyl- l-oxypyrroline-3-carboxylic acid has been determined by ENDOR spectroscopy and computer based molecular modeling. ENDOR spectra of spin-labeled L- phenylalanine and the corresponding methyl ester of L-phenylalanine and of their 8-fluoro and £-fluoro derivatives in perdeuterated methanol or chloroform/toluene exhibited well resolved resonance absorptions from protons and fluorines of the amino acid moiety. From the analysis of the dependence of the ENDOR spectra on Hq, we have identified principal hyperfine coupling (hfc) components of each …

ChemInform Abstract: Gold-Catalyzed Intramolecular Hydroamination of o-Alkynylbenzyl Carbamates: A Route to Chiral Fluorinated Isoindoline and Isoqui…

2013

Title compounds are prepared in enantiomerically pure form by the diastereoselective addition of fluorinated nucleophiles to N-(tert-butanesulfinyl)imines (I) followed by a sequence of Sonogashira cross-coupling/gold(I)-catalyzed cycloisomerization of the corresponding carbamate.

Block copolymers in giant unilamellar vesicles with proteins or with phospholipids

2013

Biocompatible, highly water-soluble, nonionic, amphiphilic block copolymers having different hydrophobic blocks and architectures, but similar molecular size and chemical nature of the hydrophilic blocks, were investigated to check for their ability to form hybrid giant unilamellar vesicles with proteins, and for their interactions with giant unilamellar phospholipid vesicles (GUV). PGM14-b-PPO34-b-PGM14 (PGM-PPO-PGM) consists of a poly(propylene oxide) middle block and outer poly(glycerol monomethacrylate) blocks. Ch-PEG32-b-lPG18 (Ch-PEG-lPG) and Ch-PEG30-b-hbPG17 (Ch-PEG-hbPG) have a linear poly(ethylene glycol) block, linked to a cholesterol end group and to a linear (lPG) or hyperbranc…

Developments in the Synthesis of Glycopeptides Containing Glycosyl l-Asparagine, l-Serine, and l-Threonine

1994

Unequivocal determination of isomeric products of reaction between 3-methyl-1-phenyl-2-pyrazoline-4,5-dione and aromatic 1,2-diamines

1999

Abstract Regioselectivity of condensation of 3-methyl-1-phenyl-2-pyrazoline-4,5-dione with aromatic 1,2-diamines is dependent on substituent present. Isomeric 3-methyl-1-phenyl-1H-pyrazolo-[3,4-b]-quinoxaline products are distinguished by comparison of their 2D z-gradient selected 1H, 15N HMBC (Heteronuclear Multiple Bond Correlation) spectra. Multiplicity of H5 signal, which is recognizable by the cross-peak for CH3(3)-N4 and H5-N4 interactions, indicates substitution in position 6 or 7. The applied method is expected to be useful for structure determinations in other positional isomers.

ChemInform Abstract: Regio- and Stereoselective Synthesis of Spiropyrrolizidines and Piperazines Through Azomethine Ylide Cycloaddition Reaction.

2016

A series of original spiropyrrolizidine derivatives has been prepared by a one-pot three-component [3 + 2] cycloaddition reaction of (E)-3-arylidene-1-phenyl-pyrrolidine-2,5-diones, l-proline, and the cyclic ketones 1H-indole-2,3-dione (isatin), indenoquinoxaline-11-one and acenaphthenequinone. We disclose an unprecedented isomerization of some spiroadducts leading to a new family of spirooxindolepyrrolizidines. Furthermore, these cycloadducts underwent retro-1,3-dipolar cycloaddition yielding unexpected regioisomers. Upon treatment of the dipolarophiles with in situ generated azomethine ylides from l-proline or acenaphthenequinone, formation of spiroadducts and unusual polycyclic fused pip…

Hydrodynamic chromatography for characterization and purification of liposomes

1989

Liposomes from α,ω-dipolar amphiphiles with a polymerizable diyne moiety in the hydrophobic chain

1982

Symmetric polymerizable α,ω-dipolar C22-diacetylenes were prepared by oxidative coupling of 10-undecynoic acid and 10-undecynol, respectively, by means of copper II salts in ethanolic solution. 10,12-Docosadiyne-1,22-diphosphate (3)—by reaction of 10,12-docosadiyne-1,22-diol (2) with POCl3—was polymerized in aqueous solution using UV irradiation to form deep blue, thermochromic solutions. By consonication of 3 with cholesterol, monolayer vesicles were formed. This was proven by encapsulation of 6-carboxyfluorescein. These monomeric vesicles were polymerized by UV light to yield stable, deep blue polymeric vesicle suspensions.

Polyether-Based Lipids Synthesized with an Epoxide Construction Kit: Multivalent Architectures for Functional Liposomes

2013

Cardopatine and isocardopatine, two novel cyclobutane substances from Cardopatium corymbosum

1978

Two new natural substances containing a cyclobutane unit, cardopatine and isocardopatine, the trans and cis isomers respectively of 5,5″ (cyclobut-1,2-ylene-diethynylene)bis 2,2′-bithiophene), together with the known α-terthienyl and 5-(but-3-en-1-ynyl)-2,2′-bithienyl, have been isolated from the roots of Cardopatium corymbosum. Evidence is given that the novel cyclobutane substances are not the products of a spontaneous dimerization of a bithienyl monomeric unit. Structure determination and conformational analysis are reported.