Incorporation of 4J-HMBC and NOE Data into Computer-Assisted Structure Elucidation with WebCocon

Abstract

Over the past decades, different software programs have been developed for the Computer-Assisted Structure Elucidation (CASE) with NMR data using with various approaches. WebCocon is one of them that has been continuously improved over the past 20 years. Here, we present the inclusion of 4JCH correlations (4J-HMBC) in the HMBC interpretation of Cocon and NOE data in WebCocon. The 4J-HMBC data is used during the structure generation process, while the NOE data is used in post-processing of the results. The marine natural product oxocyclostylidol was selected to demonstrate WebCocon’s enhanced HMBC data processing capabilities. A systematic study of the 4JCH correlations of oxocyclostylidol was performed. The application of NOEs in CASE is demonstrated using the NOE correlations of the diterpene pyrone asperginol A known from the literature. As a result, we obtained a conformation that corresponds very well to the existing X-ray structure.

Dihydroisocoumarins and Dihydroisoflavones from the Rhizomes of Dioscorea collettii with Cytotoxic Activity and Structural Revision of 2,2′-Oxybis(1,4-di-tert-butylbenzene)

“…This explained well the strong HMBC correlation from H-5 ( δ H 7.13) to C-1 ( δ C 147.8), which is apparently inconsistent with structure 2′ . In addition, all the HMBC correlations reported for 2′ [ 14 ], including the weak 4 J C,H long-range HMBC correlation from H-6 ( δ H 7.54) to C-7 ( δ C 35.0) [ 19 , 20 ], were also consistent with structure 2 . Moreover, compound 2 might be a naturally occurring dimer of 2,4-Di-tert-butylphenol (2,4-DTBP), which is a common secondary metabolite produced by various groups of organisms [ 21 ].…”

Structure elucidation of the novel synthetic cannabinoid Cumyl‐Tosyl‐Indazole‐3‐Carboxamide (Cumyl‐TsINACA) found in illicit products in Germany

“…The model has been additionally trained by implementing approximately 1500 own, fully assigned spectra of drugs and related substances. The software WebCocon (https://cocon-nmr.de/) 30–35 was used for the prediction of chemical structures based on the NMR correlation data (COSY and HMBC).…”

Advanced Methods for Natural Products Discovery: Bioactivity Screening, Dereplication, Metabolomics Profiling, Genomic Sequencing, Databases and Informatic Tools, and Structure Elucidation

“…Therefore, CASE systems have a high relevance by integrating all existing computational methods, for example, structure generation by structure assembly [361][362][363][364] and reduction [365], stochastic structure generators [366], combinatorial structure generation with restraints [367,368], convergent structure generation [369,370], fuzzy structure generation [371], chemical graph generators [42], logic engines [372], combinatorial brute force [373][374][375][376], databases of 13 C NMR chemical shifts and fragments [377,378], genetic algorithms [379,380], simulated annealing [381], evolutionary algorithms [382], expert systems [44,383], and expert systems with Density Functional Theory (DFT) [43][44][45]. In Figure 7, the main achievements of CASE systems are highlighted [39][40][41]43,384,385]. In general, CASE systems produce a set of possible structures that satisfy the experimental spectroscopic data and the CASE knowledge.…”