Recent Applications of Optical Rotatory Dispersion and Optical Circular Dichroism in Organic Chemistry

Crabbé, Pierre

doi:10.1002/9780470147108.ch3

Cited by 13 publications

(2 citation statements)

References 257 publications

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“…Thus, in addition to optical rotation measurements, optical rotatory dispersion (ORD) and electronic circular dichroism (ECD), in which the Cotton effect can be contrasted with that of a molecule of known AC, simply based on partial structure analogy, was developed and widely used. 5 In fact, useful empirical rules were developed for ORD and ECD AC proposals, although time has shown that not necessarily these rules always hold, since erroneous conclusions were eventually reached. Although highly sensitive, the disadvantage of ECD is that it requires the presence of a chromophore in the molecule under study since it uses circularly polarized light in the UV region of the electromagnetic spectrum, and therefore only those stereogenic centers located in the neighborhood of the chromophore can be assigned.…”

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Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Río

Joseph‐Nathan

2021

Natural Product Communications

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Although demonstrated in 1975, vibrational circular dichroism (VCD) finally started to popularize during this century as a reliable tool to determine the absolute configuration (AC) of organic molecules. This research field continues to be a very dynamic one, in particular for the study of natural products which are a unlimited source of chiral molecules. It therefore turns of interest to summarize the accomplishments published in recent years and to comment on some eventual difficulties that emerged in rare cases to complete the AC determination task. Therefore the aim of this review is to update VCD results for the AC assignment of natural products published from 2015 to 2019, a period in which VCD was reported in some 126 publications involving almost 300 molecules. They are organized according the type of studied metabolite allowing an easily search. The molecules correspond to 28 monoterpenes concerning 17 papers, to 42 sesquiterpenes in 14 papers, to 51 diterpenes in 19 publications, to 5 other terpenoids in three papers, to 48 aromatic molecules in 15 reports, to 20 polyketides in 10 publications, to 27 miscellaneous formulas also in 10 papers, and to 76 nitrogen containing compounds, which include alkaloids and their synthetic analogs, in 38 articles. The landscape of reviewed molecules is quite wide as it goes from simple monoterpenes, like borneol or camphor, to very relevant biological molecules like the alkaloid cocaine or tadalafil samples to distinguish genuine and counterfeit Cialis®. In addition, 5 natural products and a simple derivative published outside the reviewed period, were used to illustrate some aspects of density functional theory calculations.

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Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Río

Joseph‐Nathan

2021

Natural Product Communications

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“…The empirical use of ORD or CD to compare absolute configurations of isoflavans substituted with different chromophores like aromatic and p-benzoquinone moiety is ambiguous. Thus, UV absorption of benzene chromophore at 220-320 nm is associated with * transition [21], hence, the CE(s) in this region is used for the determination of the absolute stereochemistry. The UV assignments for p-benzoquinone chromophore were depicted as follows: 240 nm associated with * transition, 295 nm and 450 nm assigned to n* transitions [22].…”

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Antiparasitic and Antimicrobial Isoflavanquinones from Abrus schimperi

Rahman

Samoylenko

Jain

et al. 2011

Natural Product Communications

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The EtOH extract of Abrus schimperi (Fabaceae), collected in Kenya, demonstrated significant activity against Leishmania donovani promastigotes with IC50 value of 3.6 μg/mL. Bioassay-guided fractionation of CHCl3 fraction using Centrifugal Preparative TLC afforded two antiparasitic isoflavanquinones, namely amorphaquinone (1) and pendulone (2). They displayed IC50 values of 0.63 μg/mL and 0.43 μg/mL, respectively, against L. donovani promastigotes. Both the compounds were also evaluated against L. donovani axenic amastigotes and amastigotes in THP1 macrophage cultures. In addition, compounds 1 and 2 showed antiplasmodial activity against Plasmodium falciparum D6 and W2 strains, while 2 displayed antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus (each IC50 1.44 μg/mL). The 1H and 13C data of 1, not fully assigned previously, were unambiguously assigned using 1D and 2D NMR HMBC and HMQC experiments. In addition, the absolute stereochemistry of the isolated compounds 1 and 2 was revised as C-(3S) based on Circular Dichroism experiments. This appears to be the first report of amorphaquinone (1) and pendulone (2) from the genus Abrus.

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Stereochemistry of Metallocenes

Schlögl

1967

Topics in Stereochemistry

212

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Recent Applications of Optical Rotatory Dispersion and Optical Circular Dichroism in Organic Chemistry

Cited by 13 publications

References 257 publications

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Antiparasitic and Antimicrobial Isoflavanquinones from Abrus schimperi

Stereochemistry of Metallocenes

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