Search results for "computational"
showing 10 items of 5884 documents
Density Functional Theory Study of the Cycloaddition Reaction of Furan Derivatives with Masked o-Benzoquinones. Does the Furan Act as a Dienophile in…
2002
The molecular mechanism for the cycloaddition reaction between 2-methylfuran and a masked o-benzoquinone has been characterized using quantum mechanical calculations at the B3LYP/6-31G theory level. An analysis of the results on the reaction pathway shows that the reaction takes place along a polar stepwise mechanism. The first and rate-determining step corresponds to the nucleophilic attack of the furan ring on the doubly conjugated position of the 2,4-dienone system present at the masked o-benzoquinone to give a zwitterionic intermediate. Closure of this intermediate affords the formally [2 + 4] cycloadduct. For the second step two reactive channels have been characterized corresponding t…
Cycloadditions in the pyrrole series
1972
PUNAS: A Parallel Ungapped-Alignment-Featured Seed Verification Algorithm for Next-Generation Sequencing Read Alignment
2017
The progress of next-generation sequencing has a major impact on medical and genomic research. This technology can now produce billions of short DNA fragments (reads) in a single run. One of the most demanding computational problems used by almost every sequencing pipeline is short-read alignment; i.e. determining where each fragment originated from in the original genome. Most current solutions are based on a seed-and-extend approach, where promising candidate regions (seeds) are first identified and subsequently extended in order to verify whether a full high-scoring alignment actually exists in the vicinity of each seed. Seed verification is the main bottleneck in many state-of-the-art a…
Synthesis and Conformational Analysis of Tetrahydroisoquinoline-Fused 1,3,2-Oxazaphospholidines and 1,2,3-Oxathiazolidines
2008
The cyclizations of tetrahydroisoquinoline 1,2-amino alcohols with phenylphosphonic dichloride, bis(2-chloroethyl)phosphoramidic dichloride, thionyl chloride and sulfuryl chloride were utilized to synthesize 1,5,6,10b-tetrahydro-1,3,2-oxazaphospholo[4,3-a]isoquinolines (2, 3), 1,5,10,10a-tetrahydro-1,3,2-oxazaphospholo[3,4-b]isoquinolines (8, 9), 1,5,6,10b-tetrahydro-1,2,3-oxathiazolo[4,3-a]isoquinolines (4–6) anda 1,5,10,10a-tetrahydro-1,2,3-oxathiazolo[3,4-b]isoquinoline (11), which are the first representatives of these ring systems. NMR spectroscopic analysis revealed the existence of conformational equilibria that are fast on the NMR timescale. Theoretical DFT calculations pointed to t…
On the Reactivity of C(sp3)–H σ-Bonds: Oxygenation with Methyl(trifluoromethyl)dioxirane
2008
The reactivity of C–H σ-bonds of a series of 2-substituted adamantanes 2 towards methyl(trifluoromethyl)dioxirane (1) shows a consistent dependence on the electron-withdrawing ability, either inductive or by resonance, of the substituent. The results are interpreted in terms of the ability of the substrate molecule to delocalize the electronic perturbation of the reacting center at the beginning of the reaction path. The model shows that the electronic demand from the reacting C–H σ-bond is transmitted along the substrate through a chain of hyperconjugative interactions, the relative intensities of which depend on the σ-bonds involved. The substrate molecule simultaneously provides positive…
Theoretical Study of the 1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides. A DFT Study of Reaction between Trifluoromethyl Thiomethyl Azometh…
1999
The molecular mechanism for the 1,3-dipolar cycloaddition of trifluoromethyl thiomethyl azomethine ylide with acronitrile has been characterized using density functional theory methods with the B3L...
Resveratrol in Experimental Models and Humans
2018
Abstract The search for natural compounds with beneficial activity for health has been one of the great challenges since men are aware of their survival. Many elixirs and ointments have been tested as the possible treatment or remedy for diseases or even death. In traditional medicine, compounds with biological activities have been used in humans. Among them, resveratrol (RSV) is, currently, one of the most studied natural compounds by modern science. To study this polyphenol we have a series of very useful tools that allow us to investigate from molecular targets, to signaling pathways in which it is involved, as well as effects on pathologies and even health and longevity. In this chapter…
Human Leukocyte Antigen Typing Using High-Throughput DNA and RNA Sequencing and Application for Cell Line Identification
2019
Fate of several hydroxyalkyl isoprene radicals: Formation of hydroxycarbonyl compounds
2005
Abstract The fate of two hydroxyalkyl radicals derived from the oxidation of isoprene with OH radical, resulting in the formation of two hydroxycarbonyls, was investigated by means of theoretical quantum chemistry methods. All the stationary points were optimised at the UMP2/6-31G(d) level, and high-level ab initio calculations were performed at the QCISD(T)/6-31G(d) level of computation upon MP2 optimised structures in order to refine the energy of the molecules characterised. Our results show that the reaction of hydroxyalkyl radicals with O 2 is a very favoured pathway that explains the formation of the two hydroxycarbonyls optimised.