Search results for "Derivatives"
showing 10 items of 432 documents
Fluorinated Heterocyclic Compounds. A Photochemical Approach to a Synthesis of Polyfluoroaryl-1,2,4-triazoles.
2005
The reaction of some fluorinated 1,2,4-oxadiazoles in the presence of methylamine or propylamine has been investigated. The irradiation in methanol or acetonitrile leads with acceptable yields to the corresponding fluorinated 1- methyl- or 1-propyl-1,2,4-triazole.
Posaconazole concentrations in the central nervous system
2008
more susceptible to the killing activity of caspofungin. This study is the first comparing caspofungin killing activity against the closely related species C. parapsilosis, C. orthopsilosis and C. metapsilosis. Killing curves, regardless of the medium used, showed a decreasing order of susceptibility to caspofungin: C. metapsilosis . C. orthopsilosis . C. parapsilosis. Based on high echinocandin MICs for C. parapsilosis sensu stricto, in the case of isolates identified as C. parapsilosis sensu lato low MICs of echinocandins may be regarded as an indicator that an isolate is in fact C. orthopsilosis or C. metapsilosis; in the case of isolates with low echinocandin MICs, DNA-based identificat…
Synthetic derivatives of aromatic abietane diterpenoids and their biological activities
2014
Naturally occurring aromatic abietane diterpenoids (dehydroabietanes) exhibit a wide range of biological activities. A number of synthetic studies aimed at modifying the abietane skeleton in order to obtain new potential chemotherapeutic agents have been reported. In this study, the biological activities of synthetic derivatives of aromatic abietane diterpenoids are reviewed.
Prediction of Aquatic Toxicity of Benzene Derivatives to Tetrahymena pyriformis According to OECD Principles
2016
Background: Many QSAR studies have been developed to predict acute toxicity over several biomarkers like Pimephales promelas, Daphnia magna and Tetrahymena pyriformis. Regardless of the progress made in this field there are still some gaps to be resolved such as the prediction of aquatic toxicity over the protozoan T. pyriformis still lack a QSAR study focused in accomplish the OECD principles. Methods: Atom-based quadratic indices are used to obtain quantitative structure-activity relationship (QSAR) models for the prediction of aquatic toxicity. Our models agree with the principles required by the OECD for QSAR models to regulatory purposes. The database employed consists of 392 substitut…
The Reactivity of 4’-Substituted Spiro[Isoindole-1,3’-pyrazoles] Derivatives: Substitution/Elimination Reactions and Access to Biaryl Derivatives
2017
This paper describes aspects of the chemistry of 4’-substituted spiro [indole-1,3’-pyrazoles]. These compounds underwent substitution and/or elimination reactions to afford some new spiro- as well as biaryl derivatives of potential pharmaceutical relevance. Mechanistic considerations are discussed as well.
Dimesogenic ferroelectric polysiloxanes
1994
Dimesogenic polysiloxane [Si(Me) 2 O] m [Si(Me)(R)O] n (R= (CH 2 ) 3 CH(COO[CH 2 ] 11 OPhPhOCOPh(NO 2 )OC * H(Me)C 6 H 13 ) 2 are synthesized by hydrosilylation. The phase transition temperaturs are determined and the ferroelectric properties are investigated
Selective Preparation of Diamondoid Phosphonates
2014
We present an effective sequence for the preparation of phosphonic acid derivatives of the diamondoids diamantane, triamantane, [121]tetramantane, and [1(2,3)4]pentamantane. The reactions of the corresponding diamondoid hydroxy derivatives with PCl3 in sulfuric or trifluoroacetic acid give mono- as well as didichlorophosphorylated diamondoids in high preparative yields.
NMR enantiodifferentiation of triphenylphosphonium salts by chiral hexacoordinated phosphate anions
2003
BINPHAT anion—rather than TRISPHAT—is an efficient NMR chiral shift reagent for triphenylphosphonium salts containing stereogenic centers on the aliphatic side-chain. BINPHAT—rather than TRISPHAT—anion is an efficient NMR (1H and 31P) chiral shift reagent for chiral triphenylphosphonium salts.
Pyrene-benzoylthiophene Bichromophores as Selective Triplet Photosensitizers.
2006
Combination of the pyrene and benzoylthiophene units constitutes an interesting approach to design bichromophoric photosensitizers with increased intersystem crossing quantum yield and enhanced selectivity. The potential of this strategy has been illustrated in the present work by using a model photoisomerization reaction.
Photochemical intermediates of trans-Rh(CO)L2Cl where L=PMe3, PBu3, and i-Pr2HN and cis-Rh(CO)2(i-Pr2HN)Cl in frozen organic glasses
2002
International audience; The Nujol glass matrix photolyses of Rh(CO)(PMe3)2Cl (1), Rh(CO)(PBu3)2Cl (2), Rh(CO)2(i-Pr2HN)Cl (3), and Rh(CO)(i-Pr2HN)2Cl (4), have been examined. Phototolysis of 1 (λirr>400 nm) and 2 (350<λirr<400 nm) give new species, A, with carbonyl stretching bands slightly below the parent bands. In the case of 1 this species appears to give rise to a second product, C, upon either extended photolysis or annealing. High-energy photolysis of 1, 2, and 4, result in loss of CO and formation of an IR silent species, RhL2Cl. In the case of 1 a new carbonyl species, B, is observed upon high-energy photolysis or annealing of a matrix containing CO and Rh(PMe3)2Cl. B may be conver…