76835-67-1Relevant articles and documents
A Unique Combination of Two Different Quorum Sensing Systems in the β-Rhizobium Cupriavidus taiwanensis
Wakimoto, Takayuki,Nakagishi, Shiori,Matsukawa, Nao,Tani, Shuji,Kai, Kenji
supporting information, p. 1876 - 1884 (2020/07/06)
Cupriavidus taiwanensis LMG19424, a β-rhizobial symbiont of Mimosa pudica, harbors phc and tqs quorum sensing (QS), which are the homologous cell-cell communication systems previously identified from the plant pathogen Ralstonia solanacearum and the human pathogen Vibrio cholerae, respectively. However, there has been no experimental evidence reported that these QS systems function in C. taiwanensis LMG19424. We identified (R)-methyl 3-hydroxymyristate (3-OH MAME) and (S)-3-hydroxypentadecan-4-one (C15-AHK) as phc and tqs QS signals, respectively, and characterized these QS systems. The expression of the signal synthase gene phcB and tqsA in E. coli BL21(DE3) resulted in the high production of 3-OH MAME and C15-AHK, respectively. Their structures were elucidated by comparison of EI-MS data and GC/chiral LC retention times with synthetic standards. The deletion of phcB reduced cell motility and increased biofilm formation, and the double deletion of phcB/tqsA caused the accumulation of the metal chelator coproporphyrin III in its mutant culture. Although the deletion of phcB and tqsA slightly reduced its ability to nodulate on aseptically grown seedlings of M. pudica, there was no significant difference in nodule formation between LMG19424 and its QS mutants when commercial soils were used. Taken together, this is the first example of the simultaneous production of 3-OH MAME/C15-AHK as QS signals in a bacterial species, and the importance of the phc/tqs QS systems in the saprophytic stage of C. taiwanensis LMG19424 is suggested.
Chiral Surfactant-Type Catalyst: Enantioselective Reduction of Long-Chain Aliphatic Ketoesters in Water
Lin, Zechao,Li, Jiahong,Huang, Qingfei,Huang, Qiuya,Wang, Qiwei,Tang, Lei,Gong, Deying,Yang, Jun,Zhu, Jin,Deng, Jingen
, p. 4419 - 4429 (2015/05/13)
A series of amphiphilic ligands were designed and synthesized. The rhodium complexes with the ligands were applied to the asymmetric transfer hydrogenation of broad range of long-chained aliphatic ketoesters in neat water. Quantitative conversion and excellent enantioselectivity (up to 99% ee) was observed for α-, β-, γ-, δ- and ε-ketoesters as well as for α- and β-acyloxyketone using chiral surfactant-type catalyst 2. The CH/π interaction and the strong hydrophobic interaction of long aliphatic chains between the catalyst and the substrate in the metallomicelle core played a key role in the catalytic transition state. Synergistic effects between the metal-catalyzed site and the hydrophobic microenvironment of the core in the micelle contributed to high stereoselectivity. (Chemical Equation Presented).
Asymmetric synthesis of long chain β-hydroxy fatty acid methyl esters as new elastase inhibitors
Hasdemir, Belma,Onar, Huelya Elik,Yusufolu, Aye
, p. 1100 - 1105 (2012/11/07)
Herein, β-hydroxy methyl esters with an even carbon chain length of 12-20 1b-5b were synthesized by three different asymmetric reduction methods I, II III from their corresponding β-keto methyl esters 1a-5a with the aim of determining their elastase activities. In method I, chiral catalyst A was prepared from chiral ligand (R)-binaphthol 1, while in method II, chiral catalyst B was synthesized from (2R,3R)-diisopropyl tartrate 2. Chiral catalyst B has not previously been used in asymmetric borane reductions or in the asymmetric synthesis of chiral β-hydroxy methyl esters. In method III, an asymmetric reduction was catalysed by (R)-Me-CBS oxazaborolidine 3. Hydride transfer was carried out in all of these methods by BH3· SMe2. Chiral hydroxy methyl esters with an (S)-configuration were synthesized by method I and with an (R)-configuration via methods II and III. The chiral hydroxy methyl esters obtained were analysed by chiral HPLC for their ee % values. Methods I, II and III were applied to long chain β-keto methyl esters for the first time. The reduction methods I, II and III were examined in terms of reaction yield and enantiomeric excess according to carbon chain length and the variable ratio of chiral catalysts to β-keto methyl ester. The highest enantiomeric excess of 90% ee was found in method III for 12 and 14 carbon numbers.
