- Disproof of the Proposed Structures of Bradyoxetin, a Putative Bradyrhizobium japonicum Signaling Molecule, and HMCP, a Putative Ralstonia solanacearum Quorum-Sensing Molecule
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First, we revisited the reported NMR data of bradyoxetin, a putative cell density factor of Bradyrhizobium japonicum, and found some inconsistencies in the proposed structure. To elucidate the correct structure, we synthesized model oxetane compounds and confirmed that the NMR data of the synthetic compounds did not match those of the reported bradyoxetin. After reinterpreting the reported NMR data, we concluded that bradyoxetin must be chloramphenicol. Next, some derivatives of 2-hydroxy-4-((methylamino)(phenyl)methyl)cyclopentanone (HMCP), which is a putative quorum-sensing molecule of Ralstonia solanacearum, were synthesized. The NMR spectra of the synthesized compounds were completely different from those of the reported natural products. Based on theoretical studies, including the estimation of 1H and 13C NMR chemical shifts using density functional theory calculations, we confirmed the correctness of the structure of the synthesized compound. These results strongly suggest that the proposed structure of HMCP could be incorrect.
- Yajima, Arata,Katsuta, Ryo,Shimura, Mikaho,Yoshihara, Ayaka,Saito, Tatsuo,Ishigami, Ken,Kai, Kenji
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- In tandem or alone: A remarkably selective transfer hydrogenation of alkenes catalyzed by ruthenium olefin metathesis catalysts
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A system for transfer hydrogenation of alkenes, composed of a ruthenium metathesis catalyst and HCOOH, is presented. This operationally simple system can be formed directly after a metathesis reaction to effect hydrogenation of the metathesis product in a single-pot. These hydrogenation conditions are applicable to a wide range of alkenes and offer remarkable selectivity. This journal is
- Zieliski, Grzegorz Krzysztof,Samojlowicz, Cezary,Wdowik, Tomasz,Grela, Karol
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p. 2684 - 2688
(2015/04/14)
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- Ruthenium nitronate complexes as tunable catalysts for olefin metathesis and other transformations
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Novel ruthenium(ii) complexes were obtained as a result of a stoichiometric reaction of Grubbs' benzylidene second generation catalysts with 3-nitropropene. These stable complexes, formally ruthenaisoxazole N-oxide derivatives, display activity in both me
- Wdowik, Tomasz,Samojlowicz, Cezary,Jawiczuk, Magdalena,Malinska, Maura,Wozniak, Krzysztof,Grela, Karol
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supporting information
p. 674 - 676
(2013/02/25)
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- Palladium-Catalyzed Cross-Carbonylation of Aryl Iodides with Five-Membered Cyclic Olefins
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Intermolecular cross-carbonylation of aryl iodides with five-membered cyclic olefins such as dihydrofurans and cyclopentene was found to proceed by using a catalyst system of PdCl2/PPh3 under CO (3-5 atm) in the presence of a tertiary amine.With 2,3- and 2,5-dihydrofurans, 2-aroyl-4,5-dihydro- and 3-aroyl-2,3-dihydrofurans were obtained as the predominant products, respectively, while the reaction of iodobenzene with cyclopentene gave a mixture of three regioisomers of benzoylcyclopentene.The yields of the products were observed to be markedly influenced by the amount of triphenylphosphine added.
- Satoh, Tetsuya,Itaya, Tomoaki,Okuro, Kazumi,Miura, Masahiro,Nomura, Masakatsu
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p. 7267 - 7271
(2007/10/03)
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