Search results for "41"

Synthetic approaches towards huperzine A and B

2013

Huperzine A and B are potent acetylcholinesterase inhibitors and promising against Alzheimer's disease. Completed and formal total syntheses of these medically relevant alkaloids are presented and discussed.

Kinetics of photochemical isomerization of TFA-Gly-ZΔPhe into TFA-Gly-EΔPhe

2017

The kinetics of photoisomerization of trifluoroacetyl-(Z)-dehydrophenylalanylglycine into trifluoroacetyl-(E)- dehydrophenylalanylglycine was studied in the hope that light-induced reaction could be useful as a means of preparation of the E-dehydropeptides. The obtained results indicate that if this reaction carried out under irradiation with light of wavelength 360 nm it is practically irreversible and gave nearly quantitatively pure Eisomer Significantly, expected cyclic side-products were not observed in the reaction mixture, thus proving the preparative potential of the elaborated procedure.

Synthesis of 6,12-Disubstituted Methanodibenzo[b,f][1,5]dioxocins : Pyrrolidine Catalyzed Self-Condensation of 2′-Hydroxyacetophenones

2019

The preparation of unprecedented 6,12-disubstituted methanodibenzo[b,f][1,5]dioxocins from pyrrolidine catalyzed self-condensation of 2′-hydroxyacetophenones is herein described. This method provides easy access to this highly bridged complex core, resulting in construction of two C–O and two C–C bonds, a methylene bridge and two quaternary centers in a single step. The intricate methanodibenzo[b,f][1,5]dioxocin compounds were obtained in up to moderate yields after optimization of the reaction conditions concerning solvent, reaction times and the use of additives. Several halide substituted methanodibenzo[b,f][1,5]dioxocins could be prepared from correspondent 2′-hydroxyacetophenones.

Photochemistry of triazolopyridinium ylides

2000

Glycosidopyrroles. Part 4. 1-β-D-ribofuranosyl-pyrroles and indoles as potential antiviral agents

2000

The preparation of new 1-β-D-ribofuranosylpyrroles of type 8 and a new method of synthesis of 1-β-D-ribofuranosylindoles of type 10, according to the scheme, is reported. All these new derivatives showed promising chemical and physical analogies with bioactive molecules but did not show any antiviral activity againstHIV1.

Triazolopyridines 21.1 The stereochemistry of 1-[1,2,3]triazolo[1,5-a] pyridin-7-yl-4-(2H-[1,2,3]triazol-4-yl)-1,3-butadienes and triazolo ring openi…

2002

The synthesis and NMR study of the geometry of 1-[1,2,3]triazolo[1,5-a]pyridin-7-yl-4-(2H[1,2,3]triazol-4-yl)-1,3-butadienes 1a, 1b, 5 and of new 1-(6-substituted-2-pyridyl)-4-(2H[1,2,3]triazol-4-yl)-1,3-butadienes 8-10 is reported. The stereochemistry of all butadienes studied is 1E, 3E except for compound 5 that is the 1Z, 3Z stereoisomer of 1a.

Flow Behavior of Chain and Star Polymers and Their Mixtures

2018

Star-shaped polymers show a continuous change of properties from flexible linear chains to soft colloids, as the number of arms is increased. To investigate the effect of macromolecular architecture on the flow properties, we employ computer simulations of single chain and star polymers as well as of their mixtures under Poiseuille flow. Hydrodynamic interactions are incorporated through the multi-particle collision dynamics (MPCD) technique, while a bead-spring model is used to describe the polymers. For the ultradilute systems at rest, the polymers are distributed uniformly in the slit channel, with a weak dependence on their number of arms. Once flow is applied, however, we find that the…

“One Ring to Bind Them All”—Part II: Identification of Promising G-Quadruplex Ligands by Screening of Cyclophane-Type Macrocycles

2010

A collection of 26 polyammonium cyclophane-type macrocycles with a large structural diversity has been screened for G-quadruplex recognition. A two-step selection procedure based on the FRET-melting assay was carried out enabling identification of macrocycles of high affinity (ΔT1/2up to30°C) and high selectivity for the human telomeric G-quadruplex. The four selected hits possess sophisticated architectures, more particularly the presence of a pendant side-arm as well as the existence of a particular topological arrangement appear to be strong determinants of quadruplex binding. These compounds are thus likely to create multiple contacts with the target that may be at the origin of their h…

Resveratrol, MicroRNAs, Inflammation, and Cancer

2011

MicroRNAs are short noncoding RNAs that regulate the expression of many target genes posttranscriptionally and are thus implicated in a wide array of cellular and developmental processes. The expression ofmiR-155ormiR-21is upregulated during the course of the inflammatory response, but these microRNAs are also considered oncogenes due to their upregulation of expression in several types of tumors. Furthermore, it is now well established that inflammation is associated with the induction or the aggravation of nearly 25% of cancers. Therefore, the above microRNAs are thought to link inflammation and cancer. Recently, resveratrol (trans-3,4′,5-trihydroxystilbene), a natural polyphenol with ant…

Monitoring the quality of the hospital pharmacoterapeutic process by sentinel patient program

2018

To analyze the results of sentinel patient program to monitoring the  quality pharmacoterapeutic process in the hospitalized patient through  medication errors.Design: Observational, prospective and transversal study. Ambit: General hospital of 1,000 beds.From May 2011 to June 2016.  Sample: Patients with treatment prescribe within 24 hours of being admitted  with 4 or more medications.Medication error, drugs prescribed,  medications and doses dispensing, drugs administered. Safety indicators were  defined based on medication errors at each stage of the pharmacotherapeutic  process.Of the 746 patients studied, 334 had at least 1 medication error  (44.8%; IC95%: 41.7-47.8). In the 746 treatm…