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Otrzymywanie i właściwości biologiczne racemicznych i optycznie czynnych laktonów z pierścieniem aromatycznym w pozycji β

Gładkowski Witold

Wiadomości Chemiczne

2023

[Z] 77, 5-6

509--531

Natural and synthetic lactones containing an aromatic ring exhibit a number of biological properties, e.g. antiproliferative, antifeedant or antimicrobial activity. This review deals with the synthesis and biological properties of lactones containing an aromatic substituent in the β-position of the lactone ring. The described group of compounds includes halolactones, hydroxylactones, unsaturated lactones and products of reductive dehalogenation of iodolactones. In addition to chemical transformations, biotechnological methods for obtaining optically active lactones have also been described, including the use of lipases in the chemoenzymatic pathway leading to the production of halolactones, kinetic separation of hydroxylactones in the process of enzymatic transesterification, microbial hydrolytic dehalogenation of iodolactones and enantioselective hydrolysis of the lactone ring. The biological activity of the obtained β-aryllactones was also briefly characterized.

Określanie konfiguracji absolutnej za pomocą magnetycznego rezonansu jądrowego

Kołodziejska R., Jasińska L., Karczmarska A., Dramiński M.

Wiadomości Chemiczne

2008

[Z] 62, 7-8

709-732

In relation to a very limited scale of tolerance of organisms to different geometrical isomers it has been imperative to invent a method which would enable a precise and fast evaluation of a spatial structure of optically active compounds. Using a spectroscopic method of nuclear magnetic resonance (NMR) proved to be an excellent solution. In order to define an absolute configuration by means of NMR, the enantiomeric mixture must be transformed into diastereoisomeric one by adding chiral auxiliary substituents. We distinguish three types of chiral auxiliary reagents: CDAs (chiral derivatizing agents), CSAs (chiral solvating agents), CLSRs (chiral lanthanide shift reagents). Chiral derivatizing agents are the most frequently used in analyses. The condensation reaction of an auxiliary compound with enantiomer may be single or double derivatization. In case of a double derivatization, 1H NMR spectra of two diastereoisomers obtained as a result of condensation of (R)- and (S)-CDAs with the substrates are compared. The changes in the chemical shifts of the substituents L_1 (the most bulky substituent) and L_2 (the least bulky substituent) asymmetric carbon of the substrate in the two derivatives (R)- and (S)-CDAs is defined as ?[delta delta]^RS. The [delta]^RS value is the difference between the chemical shift in the (R)-CDAs derivative ([delta](R)) and (S)-CDAs derivative ([delta](S)) for the substituents L_1 ([delta delta]^RSL_1) and L_2 ([delta delta]^RSL2) (Figure 2). In case of a single derivatization, the tested enantiomer is combined with only one enantiomer ((R)- or (S)-CDA). In the single derivatization [delta delta]^AR ([delta delta]^AR = [delta](A)-[delta](R)) is the difference in the chemical shifts of the substituents L_1 and L_2 of a derivative and a free substrate (Figure 3) [1]. Among these auxiliary reagents are MPA (methoxyphenylacetic acid), MTPA (methoxytrifluoromethylphenylacetic acid), 9-AMA (9-anthrylmethoxyacetic acid), BPG (boc-phenylglycine), 9-AHA (ethyl 2-(9-anthryl)-2-hydroxyacetate), PGME (phenylglycine methyl ester), and PGDA (phenylglycine dimethyl amide). These reagents are currently being used to determine the absolute configuration of primary alcohols (Figure 4), secondary alcohols (Figure 5), tertiary alcohols, diols [2-5], triols [6], primary amines (Figure 6, 7), secondary amines (Figure 8), and carboxylic acids (Figure 9). Other methods of determining absolute configuration such as HPLC-NMR or "mix and shake" method are currently investigated - HPLC-NMR method allows determining the absolute configuration of enantiomeric mixture as well as a pure enantiomer, the use of semipreparative column allows to precisely distinguish the obtained derivatives, which undergo the spectroscopic analysis (Figure 11) [1]. The "mix and shake" method allows determining the absolute configuration in a few minutes and without any additional separation methods. The derivative/s is/are prepared by simply mixing a solid matrix-bond auxiliary reagent with a chiral substrate and NMR spectra of the resulting derivatives are obtained without any further manipulation (Figure 12) [7].