20 resultados para 4-Hydroxypyrrole-2-carboxylate
em BORIS: Bern Open Repository and Information System - Berna - Suiça
Resumo:
In the crystal structure of the title compound (systematic name: 2,3-dichlorobenzene-1,4-diol 2,3-dichlorocyclohexa-2,5-diene-1,4-dione monohydrate), C(6)H(4)Cl(2)O(2)center dot C(6)H(2)Cl(2)O(2)center dot H(2)O, the 2,3-dichloro-1,4-hydroquinone donor (D) and the 2,3-dichloro-1,4-benzoquinone acceptor (A) molecules form alternating stacks along [100]. Their molecular planes [maximum deviations for non-H atoms: 0.0133 (14) (D) and 0.0763 (14) angstrom (A)] are inclined to one another by 1.45 (3)degrees and are thus almost parallel. There are pi-pi interactions involving the D and A molecules, with centroid-centroid distances of 3.5043 (9) and 3.9548 (9) angstrom. Intermolecular O-H center dot center dot center dot O hydrogen bonds involving the water molecule and the hydroxy and ketone groups lead to the formation of two-dimensional networks lying parallel to (001). These networks are linked by C-H center dot center dot center dot O interactions, forming a three-dimensional structure.
Resumo:
OBJECTIVE: EORTC trial 30891 compared immediate versus deferred androgen-deprivation therapy (ADT) in T0-4 N0-2 M0 prostate cancer (PCa). Many patients randomly assigned to deferred ADT did not require ADT because they died before becoming symptomatic. The question arises whether serum prostate-specific antigen (PSA) levels may be used to decide when to initiate ADT in PCa not suitable for local curative treatment. METHODS: PSA data at baseline, PSA doubling time (PSADT) in patients receiving no ADT, and time to PSA relapse (>2 ng/ml) in patients whose PSA declined to <2 ng/ml within the first year after immediate ADT were analyzed in 939 eligible patients randomly assigned to immediate (n=468) or deferred ADT (n=471). RESULTS: In both arms, patients with a baseline PSA>50 ng/ml were at a>3.5-fold higher risk to die of PCa than patients with a baseline PSA
Resumo:
The anionic cluster Pt-19(CO)(22)](4-) (1), of pentagonal symmetry, reacts with CO and AuPPh3+ fragments. Upon increasing the Au:Pt-19, molar ratio, different species are sequentially formed, but only the last two members of the series could be characterized by X-ray diffraction, namely, Pt-19(CO)(24)(mu(4)-AuPPh3)(3)](-) (2) and Pt-19(CO)(24){mu(4)-Au-2(PPh3)(2)}(2)] (3).The metallic framework of the starting cluster is completely modified after the addition of CO and AuL+, and both products display the same platinum core of trigonal symmetry, with closely packed metal atoms. The three AuL+ units cap three different square faces in 2, whereas four AuL+ fragments are grouped in two independent bimetallic units in the neutral cluster 3. Electrochemical and spectroelectrochemical studies on 2 showed that its redox ability is comparable with that of the homometallic 1.
Resumo:
Pseudomonas putida GG04 and Bacillus SF have been successfully incorporated into an explosive formulation to enhance biotransformation of TNT residues and/or explosives which fail to detonate due to technical faults. The incorporation of the microorganisms into the explosive did not affect the quality of the explosive (5 years storage) in terms of detonation velocity while complete biotransformation of TNT moieties upon transfer in liquid media was observed after 5 days. The incorporated microorganisms reduced TNT sequentially leading to the formation of hydroxylaminodinitrotoluenes (HADNT), 4-amino-2,6-dinitrotoluenes; 2-amino-4,6-dinitrotoluenes, different azoxy compounds; 2,6-diaminonitrotoluenes (2,4-DAMNT) and 2,4-diaminonitrotoluenes (2,6-DAMNT). However, the accumulation of AMDNT and DAMNT (major dead-end metabolites) was effectively prevented by incorporating guaiacol and catechol during the biotransformation process.
Resumo:
New coordination polymers [M(Pht)(4-MeIm)2(H2O)]n (M=Co (1), Cu (2); Pht2−=dianion of o-phthalic acid; 4-MeIm=4-methylimidazole) have been synthesized and characterized by IR spectroscopy, X-ray crystallography, thermogravimetric analysis and magnetic measurements. The crystal structures of 1 and 2 are isostructural and consist of [M(4-MeIm)2(H2O)] building units linked in infinite 1D helical chains by 1,6-bridging phthalate ions which also act as chelating ligands through two O atoms from one carboxylate group in the case of 1. In complex 1, each Co(II) atom adopts a distorted octahedral N2O4 geometry being coordinated by two N atoms from two 4-MeIm, three O atoms of two phthalate residues and one O atom of a water molecule, whereas the square-pyramidal N2O3 coordination of the Cu(II) atom in 2 includes two N atoms of N-containing ligands, two O atoms of two carboxylate groups from different Pht, and a water molecule. An additional strong O–H⋯O hydrogen bond between a carboxylate group of the phthalate ligand and a coordinated water molecule join the 1D helical chains to form a 2D network in both compounds. The thermal dependences of the magnetic susceptibilities of the polymeric helical Co(II) chain compound 1 were simulated within the temperature range 20–300 K as a single ion case, whereas for the Cu(II) compound 2, the simulations between 25 and 300 K, were made for a linear chain using the Bonner–Fisher approximation. Modelling the experimental data of compound 1 with MAGPACK resulted in: g=2.6, |D|=62 cm−1. Calculations using the Bonner–Fisher approximation gave the following result for compound 2: g=2.18, J=–0.4 cm−1.
Resumo:
The wild-type cholecystokinin type 2 (CCK(2)) receptor is expressed in many gastrointestinal and lung tumours. A splice variant of the CCK(2) receptor with retention of intron 4 (CCK(2)Ri4sv) showing constitutive activity associated with increased tumour growth was described in few colorectal, pancreatic and gastric cancers. Given the potential functional and clinical importance of this spliceoform, its occurrence was quantitatively characterized in a broad collection of 81 gastrointestinal and lung tumours, including insulinomas, ileal carcinoids, gastrointestinal stromal tumours (GIST), gastric, colorectal and pancreatic ductal adenocarcinomas, cholangiocellular and hepatocellular carcinomas, small cell lung cancers (SCLC), non-SCLC (nSCLC) and bronchopulmonary carcinoids, as well as 21 samples of corresponding normal tissues. These samples were assessed for transcript expression of total CCK(2) receptor, wild-type CCK(2) receptor and CCK(2)Ri4sv with end-point and real-time RT-PCR, and for total CCK(2) receptor protein expression on the basis of receptor binding with in vitro receptor autoradiography. Wild-type CCK(2) receptor transcripts were found in the vast majority of tumours and normal tissues. CCK(2)Ri4sv mRNA expression was present predominantly in insulinomas (incidence 100%), GIST (100%) and SCLC (67%), but rarely in pancreatic, colorectal and gastric carcinomas and nSCLC. It was not found in wild-type CCK(2) receptor negative tumours or any normal tissues tested. CCK(2)Ri4sv transcript levels in individual tumours were low, ranging from 0.02% to 0.14% of total CCK(2) receptor transcripts. In conclusion, the CCK(2)Ri4sv is a marker of specific gastrointestinal and lung tumours. With its high selectivity for and high incidence in SCLC and GIST, it may represent an attractive clinical target.
Resumo:
Site-selective spectroscopy in hexagonal beta-NaYF4:Er3+,Yb3+ has revealed different environments for Er3+ ions (multisite formation). The low-temperature S-4(3/2) -> (I15/2Er3+)-I-4 green emission depends on the excitation wavelength associated with the F-4(7/2) Er3+ level. We have studied the effect of hydrostatic pressure on the green, red, and blue Er3+ emission upon NIR excitation at similar to 980 nm, in order to establish the role played by energy resonance conditions and the multiple Er3+ sites due to the disordered structure for the upconversion (UC) process (energy tuning). The variation of photoluminescence spectra and lifetimes as a function of pressure and temperature reveals that the origin of the high green UC efficiency of the beta-NaYF4:Er3+,Yb3+ compound is mainly due to the multisite distribution, and the low phonon energy of the host lattice.