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Synthesis and structural elucidation of a phthalide analog using NMR analysis and DFT calculations
Author(s) -
Pinto Bryan N.S.,
Teixeira Milena G.,
Alvarenga Elson S.
Publication year - 2020
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4976
Subject(s) - phthalide , chemistry , chemical shift , nmr spectra database , enantiomer , cyclopentadiene , proton nmr , carbon 13 nmr , computational chemistry , furan , interpretation (philosophy) , nuclear magnetic resonance spectroscopy , stereochemistry , spectral line , organic chemistry , astronomy , computer science , catalysis , programming language , physics
Phtalides are secondary metabolites found in several fungi with a wide range of biological activities. A novel phthalide analog was synthesized by Diels–Alder reaction between cyclopentadiene and 3,4‐dichlorofuran‐2(5 H )‐one. Quantum mechanical calculations were used in conjunction with the spectrometric methods to determine the structure of the title compound. The calculated NMR chemical shifts for eight candidate pairs of enantiomers were compared with the experimental NMR chemical shifts applying the DP4 probability and mean absolute errors methodology. DP4 analysis using 1 H and 13 C NMR chemical shifts without assignment of the signals presented 100% probability for the correct candidate structure 3d , proving the consistency of the method even without spectra interpretation. Results from theoretical calculation and NMR spectra interpretation were in agreement to the structure of rac ‐(3a R ,4 S ,4a S ,5 R ,8 S ,8a R ,9 R ,9a S )‐3a,9a‐dichloro‐3a,4,4a,5,8,8a,9,9a‐octahydro‐4,9:5,8‐dimethanonaphtho[2,3‐ c ]furan‐1(3 H )‐one.