85 research outputs found
Structural Conformers of (1,3-Dithiol-2-ylidene)ethanethioamides: The Balance Between Thioamide Rotation and Preservation of Classical Sulfur-Sulfur Hypervalent Bonds
The reaction of N-(2-phthalimidoethyl)-N-alkylisopropylamines and S2Cl2 gave 4-N-(2-phthalimidoethyl)-N-alkylamino-5-chloro-1,2-dithiol-3-thiones that quantitatively cycloadded to dimethyl or diethyl acetylenedicarboxylate to give stable thioacid chlorides, which in turn reacted with one equivalent of aniline or a thiole to give thioanilides or a dithioester. Several compounds of this series showed atropisomers that were studied by a combination of dynamic NMR, simulation of the signals, conformational analysis by DFT methods, and single crystal X-ray diffraction, showing a good correlation between the theoretical calculations, the experimental values of energies, and the preferred conformations in the solid state. The steric hindering of the crowded substitution at the central amine group was found to be the reason for the presence of permanent atropisomers in this series of compounds and the cause of a unique disposition of the thioxo group at close-to-right angles with respect to the plane defined by the 1,3-dithiole ring in the dithiafulvene derivatives, thus breaking the sulfurâsulfur hypervalent bond that is always found in this kind of compounds.Ministerio
de EconomıaÌ y Competitividad, Spain (Project CTQ2012-
31611), Junta de Castilla y LeoÌn, ConsejeriÌa
de EducacioÌn y
Cultura y Fondo Social Europeo (Project BU246A12-1), and
the European Commission, Seventh Framework Programme
(Project SNIFFER FP7-SEC-2012-312411
Transcriptional Responses of Resistant and Susceptible Fish Clones to the Bacterial Pathogen Flavobacterium psychrophilum
Flavobacterium psychrophilum is a bacterial species that represents one of the most important pathogens for aquaculture worldwide, especially for salmonids. To gain insights into the genetic basis of the natural resistance to F. psychrophilum, we selected homozygous clones of rainbow trout with contrasted susceptibility to the infection. We compared the transcriptional response to the bacteria in the pronephros of a susceptible and a resistant line by micro-array analysis five days after infection. While the basal transcriptome of healthy fish was significantly different in the resistant and susceptible lines, the transcriptome modifications induced by the bacteria involved essentially the same genes and pathways. The response to F. psychrophilum involved antimicrobial peptides, complement, and a number of enzymes and chemokines. The matrix metalloproteases mmp9 and mmp13 were among the most highly induced genes in both genetic backgrounds. Key genes of both pro- and anti-inflammatory response such as IL1 and IL10, were up-regulated with a greater magnitude in susceptible animals where the bacterial load was also much higher. While higher resistance to F. psychrophilum does not seem to be based on extensive differences in the orientation of the immune response, several genes including complement C3 showed stronger induction in the resistant fish. They may be important for the variation of susceptibility to the infection
Structure, Stereodynamics and Absolute Configuration of the Atropisomers of Hindered Arylanthraquinones
NMR of Terminal Oxygen. Part 12. SO2 and Isoelectronic Compounds with a True π Bond: 17O NMR Spectra of Sulfinylamines R-N=S=O and Sulfines RR'C=S=O. The Conformation of ortho-Substituted Diaryl Sulfines
Crystal and molecular structure of 2,6-di (o-chloro)phenyl-3,5-dimethyl-N-nitrosopiperidin-4-one(NOCDMPO)
Conformational study on aryl ketones: The structure of 2,6-dimethyl-1,5-di-(2-methyl)-propanoylnaphthalene
Encapsulated-guest rotation in a self-assembled heterocapsule directed toward a supramolecular gyroscope
The self-assembled heterocapsule 1·2, which is formed by the hydrogen bonds of tetra(4-pyridyl)-cavitand 1 and tetrakis(4-hydroxyphenyl)-cavitand 2, encapsulates 1 molecule of guests such as 1,4-diacetoxybenzene 3a, 1,4-diacetoxy-2,5-dimethylbenzene 3b, 1,4-diacetoxy-2,5-dialkoxybenzenes (3c, OCH3; 3d, OC2H5; 3e, OC3H7; 3f, OC4H9; 3g, OC5H11; 3h, OC6H13; 3i, OC8H17), 1,4-diacetoxy-2,5-difluorobenzene 4a, and 1,4-diacetoxy-2,3-difluorobenzene 4b. The X-ray crystallographic analysis of 3c@(1·2) showed that the acetoxy groups at the 1,4-positions of 3c are oriented toward the 2 aromatic cavity ends of 1·2 and that 3c can rotate along the long axis of 1·2. Thus, the 1·2 (stator) with the encapsulation guest (rotator) behaves as a supramolecular gyroscope. A variable temperature (VT) 1H NMR study in CDCl3 showed that 3a, 3b, 4a, and 4b within 1·2 rotate rapidly even at 218 K, whereas guest rotation is almost inhibited for 3h and 3i even at 323 K. In this respect, 4b with a large dipole moment is a good candidate for the rotator of 1·2. For 3câ3g, the enthalpic (ÎHâĄ) and entropic (ÎSâĄ) contributions to the free energy of activation (ÎGâĄ) for the guest-rotational steric barriers within 1·2 were obtained from Eyring plots based on line-shape analysis of the VT 1H NMR spectra. The value of ÎG⥠increased in the order 3c < 3d < 3e < 3f < 3g. Thus, the elongation of the alkoxy chains at the 2,5-positions of 3 puts the brakes on guest rotation within 1·2
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