A5087441551- Molecular spectroscopy and chirality
- Computational Drug Discovery Methods
- Analytical Chemistry and Chromatography
- Metabolomics and Mass Spectrometry Studies
- Advanced NMR Techniques and Applications
- NMR spectroscopy and applications
- Microbial Natural Products and Biosynthesis
- Protein Structure and Dynamics
- Cyclopropane Reaction Mechanisms
- Asymmetric Hydrogenation and Catalysis
- Catalytic Cross-Coupling Reactions
- Catalytic Alkyne Reactions
- Cancer therapeutics and mechanisms
- Advanced MRI Techniques and Applications
- Various Chemistry Research Topics
- Synthesis and bioactivity of alkaloids
- Synthetic Organic Chemistry Methods
- Chemical Synthesis and Analysis
- Plant biochemistry and biosynthesis
- Synthesis and biological activity
- Berberine and alkaloids research
- Alkaloids: synthesis and pharmacology
- Natural product bioactivities and synthesis
- Phytochemistry and Biological Activities
- Vanadium and Halogenation Chemistry
Corvallis Environmental Center
2017-2024
Centro Médico Sanitas A Coruña
2020
Servicio Gallego de Salud
2018
Merck & Co., Inc., Rahway, NJ, USA (United States)
2016
Wilmington University
2014
Russian Academy of Sciences
2011
University of Illinois Chicago
2008
Novosibirsk Institute of Organic Chemistry
2002-2007
Pfizer (United States)
2004-2006
Lomonosov Moscow State University
1995-1998
A computer-assisted structural elucidation (CASE-3D) strategy based on the use of isotropic and/or anisotropic NMR data is proposed to elucidate relative configuration and preferred conformation in complex natural products. The methodology involves selection conformational models through Akaike Information Criterion scoring different configurations. As illustrative examples, furnished correct already known compounds artemisinin (1) homodimericin (2). Revised structures (5 6), including their...
Turning a new leaf: The first structures isolated from Thuiaria breitfussi, the breitfussins, are presented. This structural class consists of indole–oxazole–pyrrole units. Limited quantities prevented crystallization; therefore, were solved using novel combination AFM, computer-aided structure elucidation (CASE), and DFT calculations. Visualization by AFM determined all connection points cyclic systems other substituents.
Newly described NMR experimental approaches can provide valuable structural details and a complementary means of structure verification.
Metals are important cofactors in the metabolic processes of cyanobacteria, including photosynthesis, cellular respiration, DNA replication, and biosynthesis primary secondary metabolites. In adaptation to marine environment, cyanobacteria use metallophores acquire trace metals when necessary as well reduce potential toxicity from excessive metal concentrations. Leptochelins A–C were identified structurally novel three geographically dispersed genus Leptothoe. Determination complex...
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSynthesis of Mono-, Di-, and Trisilyl-Substituted Alkenes via the Hydrosilylation Methylenecyclopropanes Catalyzed by Rh(I) ComplexesA. G. Bessmertnykh, K. A. Blinov, Yu. Grishin, N. Donskaya, E. V. Tveritinova, M. Yur'eva, I. P. BeletskayaView Author Information Department Chemistry, Moscow State University, Moscow, 119899, RussiaCite this: J. Org. Chem. 1997, 62, 17, 6069–6076Publication Date (Web):August 22, 1997Publication History Received7 August...
StrucEluc is an expert system that allows the computer-assisted elucidation of chemical structures based on inputs a series spectral data including 1D and 2D NMR mass spectra. The has been enabled to allow chemist utilize fragments stored in fragment database as well user-defined submitted by structure process. association this way shown dramatically speed up process generation from helped minimize or eliminate need for user intervention thereby further enabling vision automated elucidation....
The efficacy of neural network (NN) and partial least-squares (PLS) methods is compared for the prediction NMR chemical shifts both 1H 13C nuclei using very large databases containing millions shifts. structure description scheme used in this work based on individual atoms rather than functional groups. performances each were optimized a systematic manner described work. Both methods, analyses, produce results similar quality, but algorithm approximately 2−3 times faster.
This article coincides with the 40 year anniversary of first published works devoted to creation algorithms for computer-aided structure elucidation (CASE). The general principles on which CASE methods are based will be reviewed and present state art in this field described using, as an example, expert system Structure Elucidator.The developers systems have been forced overcome many obstacles hindering development a software application capable drastically reducing time effort required...
InChIKey is a 27-character compacted (hashed) version of InChI which intended for Internet and database searching/indexing based on an SHA-256 hash the character string. The first block encodes molecular skeleton while second represents various kinds isomerism (stereo, tautomeric, etc.). designed to be nearly unique substitute parent InChI. However, single may occasionally map two or more strings (collision). appearance collision itself does not compromise signature as collision-free hashing...
Described herein are applications of the latest version StrucEluc expert software system, enhanced to use 2D NMR data, structure elucidation 60 recently isolated natural products. In this study, selected molecules containing between 15 and 65 skeletal atoms having molecular masses ranging from 200 900 amu have been investigated. The correct was determined unambiguously for 58 these molecules. structures 75% data sets were in less than one minute, while 90% analyses required no more 30...
Abstract Identification of degradants pharmaceuticals is a necessary challenge the drug development process following subjection candidate molecules to variety physico‐chemical stresses. It would be desirable able conduct such studies on minimal amount material. As prototypical study, isolation and identification sample complex indoloquinoline alkaloid, cryptospirolepine, was undertaken after prolonged storage in DMSO solution using combination cryogenic NMR probe technology CASE...
Abstract This paper considers the strategy of StrucEluc expert system application for structure elucidation new natural products when there is a lack connectivity information that characteristic proton‐deficient molecules. It shown in this case, database search fragments using 13 C NMR spectrum as input allows an investigator to fill gaps recorded data. Algorithms and programs have been developed allow found library and/or proposed by user be embedded molecular connectivities diagrams built...
It was recently demonstrated that an IDR- (Inverted Direct Response) HSQC-TOCSY data set could be decomposed into a negatively phased direct response spectrum and positively relayed then subjected to unsymmetrical indirect covariance processing for the removal of artifacts due overlap in proton NMR molecule. Using experimentally discrete HSQC HMBC sets, it is shown pair spectra affords presentation containing long-range carbon-carbon connectivity information. The method using strychnine as...
Abstract The availability of cryogenically cooled probes permits routine acquisition data from low sensitivity pulse sequences such as inadequate and 1,1‐adequate. We demonstrate that the use cryo‐probe generated 1,1‐adequate in conjunction with HMBC dramatically improves computer‐assisted structure elucidation (CASE) both terms speed accuracy generation. In this study were obtained on two dissimilar natural products subjected to CASE analysis without incorporation two‐bond specific data....
The accuracy of (13)C chemical shift prediction by both DFT GIAO quantum-mechanical (QM) and empirical methods was compared using 205 structures for which experimental QM-calculated shifts were published in the literature. For these structures, calculated HOSE code neural network (NN) algorithms developed within our laboratory. In total, 2531 analyzed statistically processed. It has been shown that, general, QM are capable providing similar but inferior to approaches, quite frequently they...
The elucidated structure of asperjinone (1), a natural product isolated from thermophilic Aspergillus terreus, was revised using the expert system Structure Elucidator. reliability (2) confirmed 180 structures containing (3,3-dimethyloxiran-2-yl)methyl fragment (3) as basis for comparison and whose chemical shifts contradict suggested (1).
Abstract magnified image Artifacts observed in the indirect covariance NMR spectrum of HSQC‐TOCSY data have recently been analyzed and a method for their elimination proposed. More recently, unsymmetrical processing has applied HSQC HMBC spectral to afford long‐range carbon‐carbon correlation information equivalent that obtained from n , 1‐, 1, ‐ m ‐ADEQUATE spectra. We now wish describe results through application COSY or TOCSY data, which affords HSQC‐COSY fraction time required record...
The impact of LR-HSQMBC very long-range nJCH heteronuclear shift correlation data as a supplement to HMBC input for the computer-assisted structure elucidation program, Structure Elucidator®, is assessed first time. severely proton-deficient xanthone antibiotic cervinomycin A2 and alkaloid staurosporine were employed model compounds.
The elucidation of chemical structures from 2D NMR data commonly utilizes a combination COSY, HMQC/HSQC, and HMBC data. Generally COSY connectivities are assumed to mostly describe the separation protons that separated by 1 skeletal bond (3JHH), while represent carbon atoms 2 bonds (2JCH 3JCH). Obviously lengths greater than those described have been detected. Though experimental techniques recently aid in identification nature couplings detection whether coupling is 2-bond or still remains...