The Advantage of Automatic Peer-Reviewing of C-NMR Reference Data Using the CSEARCH-Protocol.

A systematic investigation of the experimental C-NMR spectra published in during the period of 1996 to 2015 with respect to their quality using CSEARCH-technology is described. It is shown that the systematic application of the CSEARCH-Robot-Referee during the peer-reviewing process prohibits at least the most trivial assignment errors and wrong structure proposals. In many cases, the correction of the assignments/chemical shift values is possible by manual inspection of the published tables; in certain cases, reprocessing of the original experimental data might help to clarify the situation, showing the urgent need for a public domain repository.

Correction: The value of universally available raw NMR data for transparency, reproducibility, and integrity in natural product research.

Correction for 'The value of universally available raw NMR data for transparency, reproducibility, and integrity in natural product research' by James B. McAlpine et al., Nat.

The value of universally available raw NMR data for transparency, reproducibility, and integrity in natural product research.

Covering: up to 2018With contributions from the global natural product (NP) research community, and continuing the Raw Data Initiative, this review collects a comprehensive demonstration of the immense scientific value of disseminating raw nuclear magnetic resonance (NMR) data, independently of, and in parallel with, classical publishing outlets. A comprehensive compilation of historic to present-day cases as well as contemporary and future applications show that addressing the urgent need for a repository of publicly accessible raw NMR data has the potential to transform natural products (NPs) and associated fields of chemical and biomedical research. The call for advancing open sharing mechanisms for raw data is intended to enhance the transparency of experimental protocols, augment the reproducibility of reported outcomes, including biological studies, become a regular component of responsible research, and thereby enrich the integrity of NP research and related fields.

NMReDATA, a standard to report the NMR assignment and parameters of organic compounds.

Even though NMR has found countless applications in the field of small molecule characterization, there is no standard file format available for the NMR data relevant to structure characterization of small molecules. A new format is therefore introduced to associate the NMR parameters extracted from 1D and 2D spectra of organic compounds to the proposed chemical structure. These NMR parameters, which we shall call NMReDATA (for nuclear magnetic resonance extracted data), include chemical shift values, signal integrals, intensities, multiplicities, scalar coupling constants, lists of 2D correlations, relaxation times, and diffusion rates.

A Critical Evaluation of the Quality of Published C NMR Data in Natural Product Chemistry.

Nuclear Magnetic Resonance spectroscopy contributes very efficiently to the structure elucidation process in organic chemistry. Carbon-13 NMR spectroscopy allows direct insight into the skeleton of organic compounds and therefore plays a central role in the structural assignment of natural products. Despite this important contribution, there is no established and well-accepted workflow protocol utilized during the first steps of interpreting spectroscopic data and converting them into structural fragments and then combining them, by considering the given spectroscopic constraints, into a final proposal of structure.

Iridoids as chemical markers of false ipecac (Ronabea emetica), a previously confused medicinal plant.

Ethnopharmacological Relevance: Several roots or rhizomes of rubiaceous species are reportedly used as the emetic and antiamoebic drug ipecac. True ipecac (Carapichea ipecacuanha) is chemically well characterized, in contrast to striated or false ipecac derived from the rhizomes of Ronabea emetica (syn. Psychotria emetica).

Xanthones, biflavanones and triterpenes from Pentadesma grandifolia (Clusiaceae): structural determination and bioactivity.

Stem bark, roots, leaves and fruits of Pentadesma grandifolia Baker f. (Clusiaceae) have been analyzed for the presence of xanthones, biflavonoids and triterpenoids. Isolated and identified structures include the xanthones cowagarcinone B (1) and alpha-mangostin (2), further the two biflavanones 3,8"-binaringenin (3) and the corresponding 3,6"-binaringenin (4), which is here reported as natural constituent for the first time.

Prenylated flavanones and flavanonols as chemical markers in Glycosmis species (Rutaceae).

Fifteen prenylated or geranylated flavanones and flavanonols were isolated from the leaf extracts of different Glycosmis species collected in Thailand and Malaysia. All structures were elucidated by spectroscopic methods, especially 1D and 2D NMR. Six compounds were described for the first time and two were only known so far as synthetic products.

(13)C-NMR spectra of santalol derivatives: a comparison of DFT-based calculations and database-oriented prediction techniques.

A systematic investigation of a series of santalol and epi-santalol derivatives by means of ab initio and density functional theory (DFT) calculations together with database-oriented prediction methods leads to a configurational reassignment within this compound class. The DFT calculations as well as the HOSE-code and neural network-based predictions allow deriving a general rule set for unambiguous assignment within this compound class. The methyl group in position 2' serves as an indication for the configuration at this stereocenter allowing easy differentiation between santalol derivatives and their diastereomers belonging to the epi-santalol series.