1530-32-1Relevant articles and documents
CATALYTIC PHOSPHORYLATION OF POLYFLUOROALKANOLS. 13. SOME AMMONIUM AND PHOSPHONIUM SALTS AS PHOSPHYRYLATION CATALYSTS
Kabachnik, M. I.,Zakharov, L. S.,Kudryatsev, I. Yu.
, p. 2553 - 2556 (1989)
It was shown that it is possible to use a series of ammonium and phosphonium salts as effective catalysts for the preparative synthesis of tris(polyfluoroalkyl)phosphates.The effect of the structure of substituted ammonium salts on their catalytic activity was studied in the phosphorylation of 1,1-dihydroperfluorobutanol by phosphorus oxychloride.It was determined that the reaction rate is effected not only by the solubility of the salt, but also by the nature of the ion pair and the steric access of the onium center for solvation by phosphoryl compounds.
Synthesis and coordination chemistry of pentadienyl ligands derived from (1 R)-(-)-myrtenal
Fecker, Ann Christin,Craciun, Bogdan-Florin,Freytag, Matthias,Jones, Peter G.,Walter, Marc D.
, p. 3792 - 3803 (2014)
With the natural product (1R)-(-)-myrtenal as the starting material, a series of chiral pentadienes (Pdl*as dimethylnopadiene (2a), methylphenylnopadiene (2b), and methylnopadiene (2c) have been prepared by Wittig reactions. Deprotonation with the Schlosser base gives the corresponding potassium pentadienides 3a-K-3c-K, whose structures were investigated by NMR spectroscopy and X-ray diffraction studies. In all cases a "U" conformation was observed. Furthermore, the coordination chemistry and electronic properties of these new pentadienyl systems were explored in several half-open trozircene complexes [(η7-C7H 7)Zr(η5-Pdl)] and their PMe3 and tBuNC adducts. Density functional theory (DFT) computations are consistent with the experimentally observed face selectivity upon metal coordination: namely, that the metal coordinates exclusively from the sterically less encumbered side.
Nucleophilic 1,1-Difluoroethylation with Fluorinated Phosphonium Salt
Deng, Zuyong,Liu, Can,Zeng, Xian-Liang,Lin, Jin-Hong,Xiao, Ji-Chang
, p. 12084 - 12090 (2016)
The fluorinated phosphonium salt (Ph3P+CF2CH3 BF4-) was shown to act as a nucleophilic 1,1-difluoroethylation agent to enable difluoroethylation of aldehydes and imines.
β-Amyrin Biosynthesis: The Methyl-30 Group of (3S)-2,3-Oxidosqualene Is More Critical to Its Correct Folding to Generate the Pentacyclic Scaffold than the Methyl-24 Group
Hoshino, Tsutomu,Miyahara, Yuri,Hanaoka, Masaki,Takahashi, Kazunari,Kaneko, Ikki
, p. 15769 - 15784 (2015)
Oxidosqualene cyclases catalyze the transformation of oxidosqualene (1) into numerous cyclic triterpenes. Enzymatic reactions of 24-noroxidosqualene (8) and 30-noroxidosqualene (9) with Euphorbia tirucalli β-amyrin synthase were conducted to examine the role of the branched methyl groups of compound 1 in the β-amyrin biosynthesis. Substrate 8 almost exclusively afforded 30-nor-β-amyrin (>95.5%), which was produced through a normal cyclization pathway, along with minor products (4.5%). However, a lack of the Me-30 group (analogue 9) resulted in significantly high production of premature cyclization products, including 6/6/6/5-fused tetracyclic and 6/6/6/6/5-fused pentacyclic skeletons (64.6%). In addition, the fully cyclized product (35.4%) having the 6/6/6/6/6-fused pentacycle was produced; however, the normally cyclized product, 29-nor-β-amyrin was present in only 18.6% of these products. The conversion yield of substrate 8 possessing a Z-Me group at the terminus was approximately twofold greater than that of compound 9 with an E-Me group. Thus, the Me-30 group is essential for the correct folding of a chair-chair-chair-boat-boat conformation of compound 1 for the production of the β-amyrin scaffold, whereas the Me-24 group exerts little influence on the normal polycyclization cascade. Here, we show that the Me-30 group plays critical roles in constructing the ordered architecture of a chair-chair-chair-boat-boat structure, in facilitating the ring-expansion reactions, and in performing the final deprotonation reaction at the correct position.
Conformational Control of Initiation Rate in Hoveyda-Grubbs Precatalysts
Gregg, Zackary R.,Griffiths, Justin R.,Diver, Steven T.
, p. 1526 - 1533 (2018)
When the coordinating isopropyl ether of the Hoveyda precatalyst is replaced by a cyclohexyl ether, it is possible to control the substituent's conformation in either the equatorial or axial position. A stereodivergent synthesis of axial and equatorial cyclohexyl vinyl ethers provided access to new ruthenium metathesis precatalysts by carbene exchange. The conformational disposition of the coordinating aryl ether was found to have a significant effect on the reactivity of the precatalyst in alkene metathesis. The synthesis of four new Ru carbene complexes is reported, featuring either the 1,3-bis(2,4,6-trimethylphenyl)dihydroimidazolylidene (H2IMes) or the 1,3-bis(2,6-diisopropylphenyl)dihydroimidazolylidene (SIPr) N-heterocyclic carbene ligand. The conformational isomers in the SIPr series were structurally characterized. Performance testing of all new precatalysts in three different ring-closing metatheses and an alkene cross metathesis illustrated superior performance by the precatalysts bearing axial coordinating ethers. Initiation rates with butyl vinyl ether were also measured, providing a useful comparison to existing Hoveyda-type metathesis precatalysts. Use of conformational control of the coordinating ether substituent provides a new way to modulate reactivity in this important class of alkene metathesis precatalysts.
Substituted dienes prepared from betulinic acid – Synthesis, cytotoxicity, mechanism of action, and pharmacological parameters
Frydrych, Ivo,Urban, Milan,?arek, Jan,Benická, Sandra,D?ubák, Petr,Gurská, Soňa,Hajdúch, Marián,Kotulová, Jana,Li?ková, Barbora,Olejníková, Denisa,Pokorny, Jan
, (2021/07/28)
A set of new substituted dienes were synthesized from betulinic acid by its oxidation to 30-oxobetulinic acid followed by the Wittig reaction. Cytotoxicity of all compounds was tested in vitro in eight cancer cell lines and two noncancer fibroblasts. Almost all dienes were more cytotoxic than betulinic acid. Compounds 4.22, 4.30, 4.33, 4.39 had IC50 below 5 μmol/L; 4.22 and 4.39 were selected for studies of the mechanism of action. Cell cycle analysis revealed an increase in the number of apoptotic cells at 5 × IC50 concentration, where activation of irreversible changes leading to cell death can be expected. Both 4.22 and 4.39 led to the accumulation of cells in the G0/G1 phase with partial inhibition of DNA/RNA synthesis at 1 × IC50 and almost complete inhibition at 5 × IC50. Interestingly, compound 4.39 at 5 × IC50 caused the accumulation of cells in the S phase. Higher concentrations of tested drugs probably inhibit more off-targets than lower concentrations. Mechanisms disrupting cellular metabolism can induce the accumulation of cells in the S phase. Both compounds 4.22 and 4.39 trigger selective apoptosis in cancer cells via intrinsic pathway, which we have demonstrated by changes in the expression of the crucial apoptosis-related protein. Pharmacological parameters of derivative 4.22 were superior to 4.39, therefore 4.22 was the finally selected candidate for the development of anticancer drug.
Progress toward a Convergent, Asymmetric Synthesis of Jervine
De Jesús Cruz, Pedro,Johnson, Jeffrey S.,Zavesky, Blane P.
supporting information, (2020/04/30)
Progress toward a convergent approach for the enantioselective synthesis of the Veratrum alkaloid jervine is presented. The two requisite fragments were stereoselectively and efficiently fashioned from economical and readily available reagents. Key reactions include (a) a highly diastereoselective Ireland-Claisen rearrangement to establish the necessary cis-relationship between the amine and methyl group on the tetrahydrofuran E-ring; (b) a diastereoselective selenoetherification reaction that enabled the assembly of the D/E oxaspiro[4.5]decene in the needed configuration; and (c) an enzymatic desymmetrization of an abundant achiral diol en route to a key four-carbon building block as a practical alternative to a protected Roche ester reduction.
Isoxazoline derivative and application thereof in agriculture
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Paragraph 0233; 0237-0238, (2020/11/25)
The invention provides an isoxazoline derivative and application of the isoxazoline derivative in agriculture. Specifically, the invention provides a compound as shown in a formula (I) or a stereoisomer, nitrogen oxide or salt of the compound as shown in the formula (I), and a preparation method thereof. In the formula (I), R1, R2, R3, R4, n, R5, R6, R7, R8 and Acy are as defined in the invention.Further, the invention provides compositions containing these compounds and use thereof in agriculture, particularly as herbicidal active ingredients for controlling unwanted plants.
Visible Light Induced Cyclization to Spirobi[indene] Skeletons from Functionalized Alkylidienecyclopropanes
Li, Quanzhe,Liu, Jiaxin,Shi, Min,Wei, Yin
supporting information, (2020/03/26)
In this paper, we revealed a metal-free and visible light photoinduced method for the rapid construction of spirobi[indene] skeletons, providing a simple and efficient way for easy access to spirobi[indene] scaffolds under mild conditions along with a broad substrate scope and good functional group tolerance.
Organic phosphine salt and optical physical property regulation and control method and application thereof (by machine translation)
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Paragraph 0045-0055, (2020/05/30)
The invention discloses an organic phosphine salt and an optical physical property regulation and control method and application, of the compound, with different alkyl chain lengths through an ion exchange reaction; to obtain the organic phosphine salt, with different alkyl chain lengths through the ion exchange reaction to control the photophysical property (Cl, Br, I), of the compound by using alkyl, chain length and heavy atom, after, ultraviolet irradiation to achieve information, encryption application 300 nm. (by machine translation)
