Synthesis and Identification of Epoxy Derivatives of 5-Methylhexahydroisoindole-1,3-dione and Biological Evaluation

Abstract

Cyclic imides belong to a well-known class of organic compounds with various biological activities, promoting a great interest in compounds with this functional group. Due to the structural complexity of some molecules and their spectra, it is necessary to use several spectrometric methods associated with auxiliary tools, such as the theoretical calculation for the structural elucidation of complex structures. In this work, the synthesis of epoxy derivatives of 5-methylhexahydroisoindole-1,3-diones was carried out in five steps. Diels–Alder reaction of isoprene and maleic anhydride followed by reaction with m-anisidine afforded the amide (2). Esterification of amide (2) with methanol in the presence of sulfuric acid provided the ester (3) that cyclized in situ to give imides 4 and 4-ent. Epoxidation of 4 and 4-ent with meta-chloroperbenzoic acid (MCPBA) afforded 5a and 5b. The diastereomers were separated by silica gel flash column chromatography, and their structures were determined by analyses of the spectrometric methods. Their structures were confirmed by matching the calculated 1H and 13C NMR chemical shifts of (5a and 5b) with the experimental data of the diastereomers using MAE, CP3, and DP4 statistical analyses. Biological assays were carried out to evaluate the potential herbicide activity of the imides. Compounds 5a and 5b inhibited root growth of the weed Bidens pilosa by more than 70% at all the concentrations evaluated.

N‐Phenylnorbornenesuccinimide derivatives, agricultural defensive, and enzymatic target selection

“…Epoxides represent another class of compounds with potential biological activity, and our research group has conducted investigations into the development of agrochemicals containing this functional group 14–17 . In one of our most recent studies, Ramos and collaborators synthesized and assessed the herbicidal activity of epoxides derived from (2 E ,4 E )‐hexa‐2,4‐dienoic acid, yielding favorable results 18 …”

Structural Elucidation by NMR Analysis Assisted by DFT Calculations of a Novel Natural Product from Conchocarpus Mastigophorus (Rutaceae)

“…Using specific quantitative parameters such as, mean absolute error (MAE) and linear fit ( R 2 ) or statistical parameters like DP4 [33] and CP3, [34] it is possible to point out the NMR data of the candidate structure that best fit the experimental NMR data, thus elucidating the correct structure for the new natural product [35] …”

“…[31] As each stereoisomer has intrinsic 1 H and 13 C chemical shifts, the theoretical NMR data of a set of candidate structures can be compared with the experimental NMR values of the new molecule. [32] Using specific quantitative parameters such as, mean absolute error (MAE) and linear fit (R 2 ) or statistical parameters like DP4 [33] and CP3, [34] it is possible to point out the NMR data of the candidate structure that best fit the experimental NMR data, thus elucidating the correct structure for the new natural product. [35] The present work describes the isolation of eleven natural products from the stem of C. mastigophorus.…”