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111.
Allyl substituted diazoalkenes undergo intramolecular 1,1-cycloaddition with complete retention of configuration to give 1,2-diazabicyclo[3.1.0]hex-2-enes. 相似文献
112.
113.
A uniqueness theorem for anticommutation relations and commutation relations of quantum spin systems
P. Combe R. Rodriguez M. Sirugue-Collin M. Sirugue 《Communications in Mathematical Physics》1978,63(3):219-235
Under quite natural assumptions we prove that a classical spin lattice has essentially two natural quantum extensions: The quantum spin lattice and the Fermi system. Moreover we derive a transformation from a commuting pair of Fermi systems to a purely anticommuting Fermi system. 相似文献
114.
115.
Microcionamides A and B, bioactive peptides from the philippine sponge Clathria (Thalysias) abietina
Davis RA Mangalindan GC Bojo ZP Antemano RR Rodriguez NO Concepcion GP Samson SC de Guzman D Cruz LJ Tasdemir D Harper MK Feng X Carter GT Ireland CM 《The Journal of organic chemistry》2004,69(12):4170-4176
Microcionamides A (1) and B (2) have been isolated from the Philippine marine sponge Clathria (Thalysias) abietina. These new linear peptides are cyclized via a cystine moiety and have their C-terminus blocked by a 2-phenylethylenamine group. Their total structures, including absolute stereochemistry, were determined by a combination of spectral and chemical methods. Compound 1 was shown to slowly isomerize about the C-36/C-37 double bond when stored in DMSO. Microcionamides A (1) and B (2) exhibited significant cytotoxicity against the human breast tumor cells lines MCF-7 and SKBR-3 and displayed inhibitory activity against Mycobacterium tuberculosis H(37)Ra. 相似文献
116.
Background
Growth hormone (GH) plays an incompletely understood role in the development of the central nervous system (CNS). In this study, we use transgenic mice expressing a growth hormone antagonist (GHA) to explore the role of GH in regulating postnatal brain, spinal cord and body growth into adulthood. The GHA transgene encodes a protein that inhibits the binding of GH to its receptor, specifically antagonizing the trophic effects of endogenous GH. 相似文献117.
[reaction: see text] Nitronic acids undergo an intramolecular 1,3-dipolar cycloaddition to unactivated double bonds, and the resulting isoxazolidines spontaneously evolve by an unprecedented in situ oxidative ring cleavage. The extension of this transformation to silyl nitronates results in a general diastereoselective construction of hydroxymethyl nitro functionalized tetrahydro-furans and -pyrrolidine having up to four consecutive stereogenic centers. 相似文献
118.
Jimenez Rodriguez C Foster DF Eastham GR Cole-Hamilton DJ 《Chemical communications (Cambridge, England)》2004,(15):1720-1721
The methoxycarbonylation of terminal or internal alkenes catalysed by palladium complexes of bis-(di-tert-butylphosphinomethyl)benzene under mild conditions leads to linear esters in 99% selectivity via a hydride mechanism. 相似文献
119.
The physicochemical interactions between an active peptide sequence derived from laminin and phospholipids have been studied. The main aim is to determine the suitability of this peptide fragment to be linked to liposome's with the purpose to develop targeting devices. Results indicate that this peptide is able to insert in lipid monolayers and also to form monomolecular layers at an air/water interface. Besides, miscibility studies carried out through compression isotherms of mixed monolayers [dipalmitoyl phosphatidylcholine (DPPC)/peptide], indicate a strong interaction at 60-80% DPPC molar composition. Studies carried out with lipid bilayers indicate that the interaction is restricted to the external face of the vesicles. Moreover, the presence of this peptide in the incubation media promotes a low level of carboxyfluorescein (CF) leakage and no fusion of vesicles. These results indicate that the association of this sequence to vesicles do not produce damage of the bilayer and can be used as potential targeting vector. 相似文献
120.