14617-86-8Relevant articles and documents
Selective Decarbonylation of Fatty Acid Esters to Linear α-Olefins
John, Alex,Dereli, Büsra,Ortunìo, Manuel A.,Johnson, Hillis E.,Hillmyer, Marc A.,Cramer, Christopher J.,Tolman, William B.
, p. 2956 - 2964 (2017/08/21)
Selective decarbonylation of p-nitrophenol esters of fatty acids to the corresponding linear α-olefins (LAOs) was achieved using palladium catalysis. After extensive ligand screening, a mixed-ligand system exploiting the trans-spanning diphosphine XantPhos and an N-heterocyclic carbene (IPr) was identified as the most effective in yielding high α-selectivity and high conversions of the ester (>98% selectivity, >90% conversion using 2.5 mol % of PdCl2 and 5 mol % of the ligands, 190 °C, 2-2.5 h). On the basis of insights from modeling at the density functional level of theory, we propose that the mixed-ligand set achieves high α-selectivity by promoting olefin dissociation from the palladium center following β-hydride elimination, which is especially facilitated both by the combined steric bias of the mixed-ligand set and by the ability of the XantPhos ligand to coordinate in both mono- and bidentate fashions.
Fingerprint lipolytic enzymes with chromogenic p-nitrophenyl esters of structurally diverse carboxylic acids
Qian, Le,Liu, Jia-Yan,Liu, Jia-Ying,Yu, Hui-Lei,Li, Chun-Xiu,Xu, Jian-He
experimental part, p. 22 - 26 (2012/02/06)
A series of structurally diverse chromogenic esters, including a new compound (4-nitrophenyl 2-methylpentanoate), has been synthesized, constituting an array of 17 substrates which could be applied to rapidly fingerprint the activity of lipases or esterases to reveal their substrates specificity and functional characteristics. Combined with genetic technology such as "data mining" and directed evolution, such fingerprints might be a promising platform for discovery of potentially useful enzymes in industrial application. The fingerprint of commercially available Lipase-B from Candida antarctica as a model enzyme was first measured to confirm the reliability of this method. Then three new enzymes mined from genomic libraries were successfully fingerprinted, revealing the functional characteristics of those enzymes. Among them, the enzyme SrfAD was founded with specific substrate preference towards cycloalkyl carboxylic esters and aromatic esters, making it more promising in synthetic utilities than other tested enzymes.
Synthesis and Spectral Properties of Chemically and Stereochemically Homogeneous Sphingomyelin and its Analogues
Bruzik, Karol S.
, p. 423 - 432 (2007/10/02)
2-N-Stearoylspingosyl-1-phosphocholines of D-erythro (2S,3R) and L-threo (2S,3S) configurations and their phosphorothioyl analogues were obtained by a purely synthetic approarch using O-methyl-N,N-di-isopropylaminophosphorochloridite as the phosphitylating reagent for the formation of the phophodiester linkage.Final products were obtained pure in yields of 70-75 percent.The structure and the purity of synthesized compounds was determined using 1H, 13C, and 31P n.m.r. spectroscopy.With respect to the structure of the sphingosine long-chain base the synthetic D-erythro-SPM was found to be identical with the natural sphigomyelin from bovine brain whereas the semisynthetic N-palmitoylshingomyelin obtained via a deacylation-reacylation pathway comprises a mixture of D-erythro- and L-thero-SPM.The phosphorothioyl analogues of sphingomyelin synthesized by addition of elementar sulphur to intermediate phosphite were separated into individual diastereomers having opposite configuration at phosphorus.The absolute configurations of diastereomers at phosphorus were assigned based on the known stereospecifity of phospholipase C in the hydrolysis of phosphorothioyl analogues of phospholipids.1H N.m.r. data of synthesized compounds suggest that the configuration at C-3 of the sphingosine influences the average conformation of sphingomyelin with respect to the angle of rotation about the C(1)-C(2) bond.
