601-57-0Relevant academic research and scientific papers
Corner Opening of Cyclopropanes by Mercury(II) and Thallium(III) and Transmetalation of the Intermediate Organomercurials. A Novel, Stereoselective Approach to Cyclobutanes and Cyclopropanes
Kocovsky, Pavel,Srogi, Jiri,Pour, Milan,Gogoll, Adolf
, p. 186 - 197 (1994)
The reactivity of the two isoelectronic cations (Hg2+ and Tl3+) toward the cyclopropane rings is compared, and further evidence for the exclusive corner selectivity for Hg2+ is provided by isotope labeling.Cleavage of cyclopropyl derivative 1 with Hg(NO3)2, followed by KBr quenching, afforded the stable, rearranged organomercurial 3, whose transmetalation has been studied.Whereas reaction of 3 with Pd(II) afforded lactol 4, treatment with Me2CuLi resulted in the formation of cyclobutanol derivative (3 -> 29); analogous conjugate addition has also been accomplished (32 -> 35).Similarly, the organomercurial 22, obtained from 21 as the major product on the Hg(II)-mediated ring-opening, reacted with Me2CuLi or AlCl3 to give the ring-closure product 21.These reactions represent a novel method for the stereoselective construction of four- and three-membered rings.The stereochemistry of the key steps of these transformations has been established by using stereospecifically deuterated substrates 1b, 3b, 21b, and 22b.
Amplifier-mediated activation of cell-penetrating peptides with steroids: Multifunctional anion transporters for fluorogenic cholesterol sensing in eggs and blood
Butterfield, Sara M.,Miyatake, Tomohiro,Matile, Stefan
, p. 325 - 328 (2009)
(Figure Presented). Off-the-shelf, pret-a-porter multianalyte sensing systems are based on the ability of cell-penetrating peptides (CPPs; see picture, blue) to mediate the export of hydrophilic anions (yellow → green) from lipid bilayer vesicles (gray). Covalent capture of hydrophobic analytes (black) with hydrophilic anions (red) produces amphiphilic anions that can activate CPPs.
MULTIFUNCTIONAL CATALYSIS-X."TAILOR-MADE" CATALYSTS FOR THE ISOMERISATION OF Δ-5 CHOLESTENONE
Fauve, A.,Kergomard, A.
, p. 1697 - 1702 (1981)
"Tailor-made" dicarboxylic acids and dihydroxynaphthalene-triethylamine complexes catalyse the isomerisation of Δ-5-cholestenone.The reaction is faster and of lower kinetic order than with simple bifunctional catalysts; the activation entropy is more favourable, but the activation enthalpy is higher, due possibly to steric and electronic interference, between the catalysing functions, which are absent in the corresponding isomerases.
A One-Step Conversion of Cholest-4-en-3-one to 24-Hydroxychol-4-en-3-one
Manley, Ronald P.,Curry, Kenneth W.,Deno, Norman C.,Meyer, Michael D.
, p. 4385 - 4387 (1980)
Cholest-4-en-3-one has been converted in one step to 24-hydroxychol-4-en-3-one in 17percent yield of crystalline material.The elimination of carbons 25-27 and the introduction of the primary alcohol group at C-24 are accomplished with CF3CO3H-H2SO4 at 0 deg C.
The importance of GLU361 position in the reaction catalyzed by cholesterol oxidase.
Kass,Sampson
, p. 2663 - 2668 (1998)
Cholesterol oxidase stereospecifically isomerizes cholest-5-en-3-one to cholest-4-en-3-one. When the base catalyst for isomerization, Glu361, is mutated to Asp, the rate of deprotonation of cholest-5-en-3-one is not affected, but protonation of the dienolic intermediate becomes rate-limiting. This may be a consequence of the large distance between the catalytic base and carbon-6 of the intermediate in the mutant enzyme.
Cascade-Amplified Time-Resolved Fluorescent Assay Driven by an Enzyme-Integrated Catalytic Compartment as an Artificial Multi-Enzyme Complex
Gao, Jie,Wang, Caihong,Wang, Jinhong,Tan, Hongliang
, p. 9629 - 9633 (2019)
We here report a simple and efficient strategy of fabricating artificial multi-enzyme complex (MEC) based on the integration of natural enzyme with catalytic compartment. As a proof of concept, this strategy was demonstrated by selecting cholesterol oxidase (ChOx) and CeIII-based nanoscale coordination polymer (Ce-NCP) with peroxidase-like activity as the models, which forms ChOx@Ce-NCP. Benefitting from the confinement and sheltering effects of Ce-NCP, superior cascade activity and stability in harsh environments were achieved in ChOx@Ce-NCP. Meanwhile, the distinct advantage of ChOx@Ce-NCP has also been highlighted by its negligible substrate inhibition effect and adjustable mass ratio of building blocks. Upon the doping of TbIII in ChOx@Ce-NCP, a luminescent artificial MEC (ChOx@Ce-NCP:Tb) was further fabricated to drive a cascade amplified time-resolved fluorescent assay within a confined space, showing high sensitivity and specificity toward cholesterol.
Cyclo-SEM: A new carbonyl protecting group
Lipshutz, Bruce H.,Mollard, Paul,Lindsley, Craig,Chang, Virginia
, p. 1873 - 1876 (1997)
Conversion of aldehydes and ketones to 1,3-dioxanes with 2-trimethylsilyl-1,3-propanediol affords carbonyl-protected products, ultimately susceptible to unmasking with LiBF4 in THF.
A colorimetric nanoprobe based on enzyme-immobilized silver nanoparticles for the efficient detection of cholesterol
Dewangan, Lakshita,Korram, Jyoti,Karbhal, Indrapal,Nagwanshi, Rekha,Jena, Vinod K.,Satnami, Manmohan L.
, p. 42085 - 42095 (2019)
A large number of cardiovascular diseases have recently become of serious concern throughout the world. Herein, we developed a colorimetric probe based on functionalized silver nanoparticles (AgNPs) for the efficient sensing of cholesterol, an important cardiovascular risk marker. A simple sodium borohydride reduction method was employed to synthesize the AgNPs. The cholesterol oxidase (ChOx)-immobilized AgNPs interact with free cholesterol to produce H2O2 in proportion to the concentration of cholesterol, resulting in decreased AgNP absorbance (turn-off) at 400 nm due to electron transfer between the AgNPs and H2O2. The response of the sensor can also be observed visually. The absorption intensity of the AgNPs is recovered (turn-on) upon the addition of sodium dodecyl sulfate due to the inhibition of ChOx. This on-off mechanism was effectively applied to detect cholesterol within the concentration range 10-250 nM with a low detection limit of approximately 0.014 nM. Moreover, the selectivity of the sensor toward cholesterol was analyzed in the presence of a range of interfering organic substances such as glucose, urea, and sucrose. Finally, the potential of the proposed sensor was evaluated using real samples.
Synthesis and evaluation of cationic lipids bearing cholesteryl groups for gene delivery in vitro
Zhu, Man-Zhou,Wu, Qi-Hua,Zhang, Guisheng,Ren, Tan,Liu, Dexi,Guo, Qing-Xiang
, p. 2207 - 2213 (2002)
A series of cationic lipids were designed and synthesized as vectors for gene delivery. The lipids contain a ketal moiety as a linker and a cholesteryl group as a hydrophobic tail. The framework of cholesteryl derivatives could increase the stability of liposomes by stabilizing the bilayers and their complexes with DNA to improve the transfection efficiency. The ketal bonds in lipids should easily degrade in an acidic environment in a cell (pH = 2-5) after transfection, resulting in little toxicity; in the neutral environment outside of cells (pH = 7), they should be stable as gene carriers. Gene transfer experiments in vitro with BL-6, 3LL, 293, 3T3, and Hela cells were performed. The results show that the gene transfection activity of three lipids is quite high, with least toxicity to cells under the experimental conditions.
A cathodic luminol-based electrochemiluminescence biosensor for detecting cholesterol using 3D-MoS2-PANI nanoflowers and Ag nanocubes for signal enhancement
Ou, Xin,Tan, Xingrong,Liu, Xiaofang,Chen, Hongmei,Fan, Yu,Chen, Shihong,Wei, Shaping
, p. 66409 - 66415 (2015)
A sensitive cathodic luminol-based electrochemiluminescence (ECL) biosensor for detecting cholesterol was fabricated with three-dimensional MoS2-polyaniline (3D-MoS2-PANI) nanoflowers and Ag nanocubes (AgNCs) for signal enhancement. In this study, the synthesized 3D-MoS2-PANI-AgNCs nanocomposites with a large surface area were used as a matrix for loading a high amount of cholesterol oxidase (ChOx). Subsequently, the loaded ChOx efficiently catalyzed the oxidation of cholesterol to produce H2O2in situ, which could promote the oxidation of luminol to generate a cathodic ECL signal. In addition, 3D-MoS2-PANI-AgNCs nanocomposites accelerate the decomposition of H2O2 into reactive oxygen species (ROSs), which increase the ECL intensity. Due to the integration of the properties of 3D-MoS2-PANI nanoflowers and AgNCs, the proposed cholesterol biosensor exhibits a wide linear response range from 3.3 nM to 0.45 mM with a low detection limit of 1.1 nM.
