30414-54-1Relevant articles and documents
Synthesis of a biotin-labeled quorum-sensing molecule: Towards a general method for target identification
Spandl, Richard J.,Nicholson, Rebecca L.,Marsden, David M.,Hodgkinson, James T.,Su, Xianbin,Thomas, Gemma L.,Salmond, George P. C.,Welch, Martin,Spring, David R.
, p. 2122 - 2126 (2008)
The synthesis of bacterial quorum-sensing regulator N- (3-oxohexanoyl)-L- homoserine lactone (OHHL) and biotin-tagged OHHL is reported. The latter will be applied to developing a general method to address the 'target identification problem' in chemical genetics. Georg Thieme Verlag Stuttgart.
Electrochemical synthesis of versatile ammonium oxides under metal catalyst-, exogenous-oxidant-, and exogenous-electrolyte-free conditions
Yuan, Yong,Li, Liang-Sen,Zhang, Lin,Wang, Feng,Jiang, Lin,Zuo, Lin,Wang, Qi,Hu, Jian-Guo,Lei, Aiwen
supporting information, p. 2768 - 2771 (2021/03/23)
An electrochemical oxidative cross-coupling reaction between 2.5-substituted-pyrazolin-5-ones and ammonium thiocyanate has been developed, which resulted in a series of unprecedented cross-coupling products under metal catalyst-, exogenous-oxidant-, and exogenous-electrolyte-free conditions. It is worth noting that since the resulting cross-coupling products are nearly insoluble in MeCN, the pure product could be afforded without silica gel column purification. In addition, the prepared ammonium oxides are versatile building blocks for synthesizing functionalized pyrazole derivatives.
Metabolites of the Anaerobic Degradation of n-Hexane by Denitrifying Betaproteobacterium Strain HxN1
Küppers, Julian,Mitschke, Nico,Heyen, Simone,Rabus, Ralf,Wilkes, Heinz,Christoffers, Jens
, p. 373 - 380 (2019/11/19)
The constitutions of seven metabolites formed during anaerobic degradation of n-hexane by the denitrifying betaproteobacterium strain HxN1 were elucidated by comparison of their GC and MS data with those of synthetic reference standards. The synthesis of 4-methyloctanoic acid derivatives was accomplished by the conversion of 2-methylhexanoyl chloride with Meldrum's acid. The β-oxoester was reduced with NaBH4, the hydroxy group was eliminated, and the double bond was displaced to yield the methyl esters of 4-methyl-3-oxooctanoate, 3-hydroxy-4-methyloctanoate, (E)-4-methyl-2-octenoate, and (E)- and (Z)-4-methyl-3-octenoate. The methyl esters of 2-methyl-3-oxohexanoate and 3-hydroxy-2-methylhexanoate were similarly prepared from butanoyl chloride and Meldrum's acid. However, methyl (E)-2-methyl-2-hexenoate was prepared by Horner–Wadsworth–Emmons reaction, followed by isomerization to methyl (E)-2-methyl-3-hexenoate. This investigation, with the exception of 4-methyl-3-oxooctanoate, which was not detectable in the cultures, completes the unambiguous identification of all intermediates of the anaerobic biodegradation of n-hexane to 2-methyl-3-oxohexanoyl coenzyme A (CoA), which is then thiolytically cleaved to butanoyl-CoA and propionyl-CoA; these two metabolites are further transformed according to established pathways.
Inversion of cpADH5 Enantiopreference and Altered Chain Length Specificity for Methyl 3-Hydroxyalkanoates
Ensari, Yunus,Dhoke, Gaurao V.,Davari, Mehdi D.,Bocola, Marco,Ruff, Anna Jo?lle,Schwaneberg, Ulrich
, p. 12636 - 12645 (2017/09/18)
Expanding the substrate scope of enzymes opens up new routes for synthesis of valuable chemicals. Ketone-functionalized fatty acid derivatives and corresponding chiral alcohols are valuable building blocks for the synthesis of a variety of chemicals including pharmaceuticals. The alcohol dehydrogenase from Candida parapsilosis (cpADH5) catalyzes the reversible oxidations of chiral alcohols and has a broad substrate range; a challenge for cpADH5 is to convert alcohols with small substituents (methyl or ethyl) next to the oxidized alcohol moiety. Molecular docking studies revealed that W286 is located in the small binding pocket and limits the access to substrates that contain aliphatic chains longer than ethyl substituent. In the current manuscript, we report that positions L119 and W286 are key residues to boost oxidation of medium chain methyl 3-hydroxy fatty acids; interestingly the enantiopreference toward methyl 3-hydroxybutyrate was inverted. Kinetic characterization of W286A showed a 5.5 fold increase of Vmax and a 9.6 fold decrease of Km values toward methyl 3-hydroxyhexanoate (Vmax: 2.48 U mg? and Km: 4.76 mm). Simultaneous saturation at positions 119 and 286 library yielded a double mutant (L119M/W286S) with more than 30-fold improved activity toward methyl 3-hydroxyoctanoate (WT: no conversion; L119M/W286S: 30 %) and inverted enantiopreference (S-enantiomer ≥99 % activity decrease and R-enantiomer >20-fold activity improvement) toward methyl 3-hydroxybutyrate.
Isolation of the antibiotic pseudopyronine B and SAR evaluation of C3/C6 alkyl analogs
Bouthillette, Leah M.,Darcey, Catherine A.,Handy, Tess E.,Seaton, Sarah C.,Wolfe, Amanda L.
supporting information, p. 2762 - 2765 (2017/05/29)
Natural products are an abundant source of structurally diverse compounds with antibacterial activity that can be used to develop new and potent antibiotics. One such class of natural products is the pseudopyronines. Here we present the isolation of pseudopyronine B (2) from a Pseudomonas species found in garden soil in Western North Carolina, and SAR evaluation of C3 and C6 alkyl analogs of the natural product for antibacterial activity against Gram-positive and Gram-negative bacteria. We found a direct relationship between antibacterial activity and C3/C6 alkyl chain length. For inhibition of Gram-positive bacteria, alkyl chain lengths between 6 and 7 carbons were found to be the most active (IC50?=?0.04–3.8?μg/mL) whereas short alkyl chain analogs showed modest activity against Gram-negative bacteria (IC50?=?223–304?μg/mL). This demonstrates the potential for this class of natural products to be optimized for selective activity against either Gram-positive or Gram-negative bacteria.
Regioselective synthesis of substituted piperidine-2,4-diones and their derivatives via Dieckmann cyclisations
Marson, Charles M.,Yau, Kin Cheung
, p. 7459 - 7469 (2015/08/24)
Abstract A flexible route to piperidine-2,4-diones variously substituted at the 6-, 5,6- and 2,6-positions, both with and without 1-substitution, is described; no N-protective group is required. A related regioselective Dieckmann cyclisation is also described that uses Davies' α-methylbenzylamine auxiliary and affords 6-substituted piperidine-2,4-diones enantioselectively.
Characterization of FabG and FabI of the Streptomyces coelicolor dissociated fatty acid synthase
Singh, Renu,Reynolds, Kevin A.
, p. 631 - 640 (2015/03/31)
Streptomyces coelicolor produces fatty acids for both primary metabolism and for biosynthesis of the secondary metabolite undecylprodiginine. The first and last reductive steps during the chain elongation cycle of fatty acid biosynthesis are catalyzed by FabG and FabI. The S. coelicolor genome sequence has one fabI gene (SCO1814) and three likely fabG genes (SCO1815, SCO1345, and SCO1846). We report the expression, purification, and characterization of the corresponding gene products. Kinetic analyses revealed that all three FabGs and FabI are capable of utilizing both straight and branched-chain β-ketoacyl-NAC and enoyl-NAC substrates, respectively. Furthermore, only SCO1345 differentiates between ACPs from both biosynthetic pathways. The data presented provide the first experimental evidence that SCO1815, SCO1346, and SCO1814 have the catalytic capability to process intermediates in both fatty acid and undecylprodiginine biosynthesis.
Site-selective aliphatic C-H bromination using N -bromoamides and visible light
Schmidt, Valerie A.,Quinn, Ryan K.,Brusoe, Andrew T.,Alexanian, Erik J.
supporting information, p. 14389 - 14392 (2014/12/10)
Transformations that selectively functionalize aliphatic C-H bonds hold significant promise to streamline complex molecule synthesis. Despite the potential for site-selective C-H functionalization, few intermolecular processes of preparative value exist. Herein, we report an approach to unactivated, aliphatic C-H bromination using readily available N-bromoamide reagents and visible light. These halogenations proceed in useful chemical yields, with substrate as the limiting reagent. The site selectivities of these radical-mediated C-H functionalizations are comparable (or superior) to the most selective intermolecular C-H functionalizations known. With the broad utility of alkyl bromides as synthetic intermediates, this convenient approach will find general use in chemical synthesis.
Highly atom-efficient oxidation of electron-deficient internal olefins to ketones using a palladium catalyst
Mitsudome, Takato,Yoshida, Syuhei,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
, p. 5961 - 5964 (2013/06/27)
A 100 % atom-efficient synthesis of ketones from electron-deficient internal olefins was achieved using O2 as a "green" oxidant (see scheme, DMA=N,N-dimethylacetamide, EWG=electron-withdrawing group). Various electron-deficient olefins were oxidized to the corresponding ketones with over 99 % selectivity and without the formation of olefin isomers or their oxidized products. Copyright
A mild titanium-catalyzed synthesis of functionalized amino coumarins as fluorescence labels
Wirtz, Lisa,Kazmaier, Uli
supporting information; experimental part, p. 7062 - 7065 (2012/01/05)
In contrast to Bronsted and other Lewis acids ClTi(OiPr)3 is especially suited to catalyze the formation of amino-substituted coumarins from aminophenols and functionalized β-oxo esters in a Pechmann condensation. This straightforward protocol allows the synthesis of fluorescence labels and false fluorescent neurotransmitters.
