- Ruthenium-NHC-Diamine Catalyzed Enantioselective Hydrogenation of Isocoumarins
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A novel and practical chiral ruthenium-NHC-diamine system is disclosed for the enantioselective hydrogenation of isocoumarins, which provides a new concept to apply (chiral) NHC ligands in asymmetric catalysis. A variety of optically active 3-substituted 3,4-dihydroisocoumarins were obtained in excellent enantioselectivities (up to 99% ee). Moreover, this methodology was utilized in the synthesis of O-methylmellein, mellein, and ochratoxin A.
- Li, Wei,Wiesenfeldt, Mario P.,Glorius, Frank
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supporting information
p. 2585 - 2588
(2017/03/08)
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- First synthesis of a stable isotope of Ochratoxin A metabolite for a reliable detoxification monitoring
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Due to its toxicity and presence in numerous food products, Ochratoxin A (OTA) has drawn attention for decades. This article summarizes the first synthesis of a labeled analogue of Ochratoxin α (OTα), one of the main products generated by the metabolization of OTA by microorganisms. This synthesis also led to a new labeled analogue of OTA with the deuteration located on the dihydroisocoumarin moiety allowing thus both the accurate quantification of OTA and OTα and the establishing of a reliable detoxification rate.
- Bouisseau, Anais,Roland, Aurelie,Reillon, Florence,Schneider, Remi,Cavelier, Florine
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supporting information
p. 3888 - 3890
(2013/09/02)
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- Synthesis of analogues of ochratoxin A
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Four analogues of ochratoxin A (OTA) differing for the aminoacidic moiety were synthesised using ochratoxin (OTα) as the starting material. The condensation reaction between protected amino acids and OT, carried out in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC?HCl) and N-hydroxybenzotriazole (HOBt) as coupling agents, followed by deprotection and PTLC purification afforded OTA alanine, leucine, serine and tryptophane analogues in satisfactory yields (33-47%, based on OT).
- Plastina, Pierluigi,Fazio, Alessia,Attya, Mohamed,Sindona, Giovanni,Gabriele, Bartolo
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p. 1799 - 1805
(2020/03/18)
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- Total synthesis and cytotoxicity evaluation of all ochratoxin A stereoisomers
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The mycotoxin ochratoxin A is a potent inhibitor of the protein biosynthesis and known to be cytotoxic in nanomolar concentrations. In order to investigate the relationship between stereochemistry and cytotoxicity of this compound, all four ochratoxin A stereoisomers have been synthesized. Using the liver cell line Hep G2, the compounds were tested for cytotoxic and apoptotic potential. It could be shown, that the l-configuration of the phenylalanine moiety of the molecule is mostly responsible for the high cytotoxicity of ochratoxin A while the stereocenter at the dihydroisocoumarine structure is of less importance.
- Cramer, Benedikt,Harrer, Henning,Nakamura, Kazuhiko,Uemura, Daisuke,Humpf, Hans-Ulrich
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experimental part
p. 343 - 347
(2010/04/05)
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- A new and expedient total synthesis of ochratoxin A and d 5-ochratoxin A
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A new total synthesis of the mycotoxin ochratoxin A (OTA) is presented, in which it is prepared in 9% overall yield from commercially available substrates. The key step consists of the condensation reaction between protected L-phenylalanine and 5-chloro-8-hydroxy-3-methyl-1-oxoisochromane-7-carboxylic acid (ochratoxin α, OTα). The same strategy could be successfully applied to L-d5-phenylalanine, leading to the first total synthesis of d5-OTA, a molecular tracer for the detection and analytical quantification of the natural mycotoxin in food samples by means of stable isotope dilution assay (SIDA). Georg Thieme Verlag Stuttgart.
- Gabriele, Bartolo,Attya, Mohamed,Fazio, Alessia,Di Donna, Leonardo,Plastina, Pierluigi,Sindona, Giovanni
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body text
p. 1815 - 1820
(2010/02/28)
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