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101.
Gerhard Buchbauer Gabriele Püspök Adelheid Angermayer Elisabeth Silbernagel Marisa Manz 《Monatshefte für Chemie / Chemical Monthly》1987,118(3):387-398
The synthesis of 4-(3,3-dimethyl-2-exo-norbornyl)-2-methyl-2-buten-1-ol (5), an analogue of -santalol (1) has been described. One route to5 starts with isocamphenilanyl propionic acid (8) which can be prepared in 4 steps from isocamphenilanic acid (9). Also 4 steps lead from8 to the target molecule5 with an overall yield of 24%. By a second and more convergent route, starting from the very easily obtainable bicyclic ketone19, the allylic alcohol5 could be obtained again in 4 steps, but this time with an overall yield of 1.3%. A new and easy synthesis of isocamphenilanyl acetic acid (15), a potential starting material to5, has been described, also the preparation of some new isocamphane derivatives.
26. Mitt:Buchbauer G,Pernold W,Ittner M,Ahmadi MF,Dobner R,Reidinger R (1985) Monatsh Chem 116: 1209 相似文献
102.
Kozlowski MC Dixon SL Panda M Lauri G 《Journal of the American Chemical Society》2003,125(22):6614-6615
Quantitative structure selectivity relationship (QSSR) models are described that provide consistently reliable predictions for the asymmetric addition of Et2Zn to PhCHO catalyzed by beta-amino alcohols. Statistically valid two-variable linear regression models that correlate the structures of the chiral catalysts with their enantioselectivities are obtained from three-dimensional physical property grids. The strength of the present method is that statistical models obtained from a small set of experimentally determined selectivities and relatively simple theoretical calculations yield selectivity predictions that are as accurate as those derived from higher-level calculations of transition-structure energies. Only minutes of computing time are required. Simple models are obtained which permit straightforward physical interpretation and generate realistic predictions. 相似文献
103.
Marisa Belicchi-Ferrari Franco BisceglieChiara Cavalieri Giorgio PelosiPieralberto Tarasconi 《Polyhedron》2007
This paper reports the synthesis and characterization of six compounds of copper(I), stabilized in its reduced state by two triphenylphosphines, in which 4-fluorobenzaldehyde thiosemicarbazone and N-methylthiosemicarbazone act as chelating through their sulfur and imino nitrogen. The three oxoanions that have been chosen, NO3−, SO42− and CH3COO−, play an important role: their oxygens are bad competitors with the imino nitrogen of the thiosemicarbazone moiety and moreover they form strong charge assisted hydrogen bondings that stabilize the neutral form of the ligand. The overall packing is determined by intermolecular phenyl–phenyl van der Waals interactions. 相似文献
104.
Miyamoto S Martinez GR Martins AP Medeiros MH Di Mascio P 《Journal of the American Chemical Society》2003,125(15):4510-4517
Peroxynitrite (ONOO-), a biologically active species, can induce lipid peroxidation in biological membranes, thereby leading to the formation of various hydroperoxides. We report herein on the formation of singlet molecular oxygen [O(2) ((1)Delta(g))] in the reaction of peroxynitrite with linoleic acid hydroperoxide (LAOOH) or (18)O-labeled LAOOH. The formation of O(2) ((1)Delta(g)) was characterized by (i) dimol light emission in the red spectral region (lambda > 570 nm) using a red-sensitive photomultiplier; (ii) monomol light emission in the near-infrared region (lambda = 1270 nm) with a liquid nitrogen-cooled germanium diode or a photomultiplier coupled to a monochromator; (iii) the enhacing effect of deuterium oxide on chemiluminescence intensity, as well as the quenching effect of sodium azide; and (iv) chemical trapping of O(2) ((1)Delta(g)) or (18)O-labeled O(2) ((1)Delta(g)) with the 9,10-diphenylanthracene (DPA) and detection of the corresponding DPAO(2) or (18)O-labeled DPA endoperoxide by HPLC coupled to tandem mass spectrometry. Moreover, the presence of O(2) ((1)Delta(g)) was unequivocally demonstrated by a direct spectral characterization of the near-infrared light emission attributed to the transition of O(2) ((1)Delta(g)) to the triplet ground state. For the sake of comparison, O(2) ((1)Delta(g)) deriving from the thermolysis of the endoperoxide of 1,4-dimethylnaphthalene or from the H(2)O(2)/hypochlorite and H(2)O(2)/molybdate systems were also monitored. These novel observations identified the generation of O(2) ((1)Delta(g)) in the reaction of LAOOH with peroxynitrite, suggesting a potential O(2) ((1)Delta(g))-dependent mechanism that contributes to cytotoxicity mediated by lipid hydroperoxides and peroxynitrite reactions in biological systems. 相似文献
105.
Yingpei Zhang Catherine Haskins Marisa Lopez-Cruzan Jianhua Zhang Victoria E Centonze Brian Herman 《Microscopy and microanalysis》2004,10(4):442-448
Apoptosis plays an important role in many physiological and pathological processes. The initiation and execution of the cell death program requires activation of multiple caspases in a stringently temporal order. Here we describe a method that allows real-time observation of caspase activation in situ in live cells based on fluorescent resonance energy transfer (FRET) measurement using the prism and reflector imaging spectroscopy system (PARISS). When a fusion protein consisting of CFP connected to YFP via an intervening caspase substrate that has been targeted to a specific subcellular location is excited with a light source whose wavelength matches the cyan fluorescent protein (CFP) excitation peak, the energy absorbed by the CFP fluorophore is not emitted as fluorescence. Instead, the excitation energy is absorbed by the nearby yellow fluorescent protein (YFP) fluorophore that is covalently linked to CFP through a short peptide containing the caspase substrate. Cleavage of the linker peptide by caspases results in loss of FRET due to the separation of CFP and YFP fluorophores. Using a mitochondrially targeted CFP-caspase 3 substrate-YFP construct (mC3Y), we demonstrate for the first time that there is caspase-3-like activity in the mitochondrial matrix of some cells at very late stage of apoptosis. 相似文献
106.
Santo M Giacomelli L Cattana R Silber J Blanco MM Schapira CB Perillo IA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(7):1399-1407
The solvatochromism in 8-hydroxy-1,6-naphthyridin-5(6H)-one-7-carboxylic acid methyl ester (1), 5-hydroxy-1,7-naphthyridin-8(7H)-one-6-carboxylic acid methyl ester (2), and 4-hydroxy-2-methyl-1(2H)-isoquinolone-3-carboxylic acid methyl ester (3), has been studied in solvents of different polarity and hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) ability. The relative stabilities of isomers for these naphthyridine derivatives and their interaction with the solvent are reported. Two intramolecular hydrogen-bonded structures contribute to the ground state of compound 1. Temperature effects on the absorption bands were recorded to analyse the possible equilibrium between covalent and zwitterionic forms. The formation of zwitterionic species was observed only in HBD solvents, from which is inferred the solvent assistance in the proton transference. AM1 and PM3 semi-empirical calculations were used in support of the proposed interpretations. 相似文献
107.
Cabeza M Bratoeff E Flores E Ramírez E Calleros J Montes D Quiroz A Heuze I 《Chemical & pharmaceutical bulletin》2002,50(11):1447-1452
The pharmacological activity of several 16-bromosubstituted trienediones 4 and 5, 16-methyl substituted dienediones 6 and 7 and the 16-methyl substituted trienedione 8 was determined on gonadectomized hamster seminal vesicles by measuring the in vitro conversion of testosterone (T) to dihydrotestosterone (DHT) as 5alpha-reductase inhibitors and also the ability of these steroids to bind to the androgen receptor. Steroids 6 and 7 when injected together with T decreased the weight of the seminal vesicles thus showing an antiandrogenic effect. Compounds 5 and 6 reduced substantially the conversion of T to DHT and therefore can be considered good inhibitors for the enzyme 5alpha-reductase; however both steroids failed to form a complex with the androgen receptor. On the other hand compound 7 which showed a very small inhibitory activity for the enzyme 5alpha-reductase, exhibited a very high affinity for the androgen receptor and thus can be considered an effective antiandrogen. This compound also reduced substantially the weight of the seminal vesicles. Steroids 4 and 8 did not reduce the weight of the seminal vesicles and exhibited a low affinity for the androgen receptor; 8 showed a weak 5alpha-reductase inhibitory activity, whereas 4 exhibited a weak androgenic effect. 相似文献
108.
Santos Lidya B. Striebeck Maria V. Crespi Marisa S. Ribeiro Clovis A. De Julio Marcelo 《Journal of Thermal Analysis and Calorimetry》2015,122(1):21-32
Journal of Thermal Analysis and Calorimetry - Recently, biochar was introduced as a bioadsorbent material to remove various contaminants in effluents, such as pigments, dyes, heavy metals,... 相似文献
109.
Fernanda M. Prado Alexsandra C. Scalfo Sayuri Miyamoto Marisa H.G. Medeiros Paolo Di Mascio 《Photochemistry and photobiology》2020,96(3):560-569
Singlet molecular oxygen is a reactive species involved in biological oxidative processes. The major cellular targets of singlet molecular oxygen are unsaturated fatty acids in the membrane, as well as nucleic acids and proteins. The aim of this study was to investigate whether lipids and commercial hydroperoxides generate singlet molecular oxygen, in presence of nitronium and activated nitronium ion. For this purpose, monomol light emitted in the near-infrared region (λ = 1270 nm) was used to monitor singlet molecular oxygen decay in different solvents, with different hydroperoxides and in the presence of azide. Direct measurements of the singlet molecular oxygen spectrum at 1270 nm recorded during the reaction between lipids and commercial hydroperoxides and nitronium ions unequivocally demonstrated the formation of this excited species. 相似文献
110.