- Development of an Efficient Synthesis of rac-3-Demethoxyerythratidinone via a Titanium(III) Catalyzed Imine-Nitrile Coupling
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We herein describe the evolution of a rapid, high-yielding synthesis of the erythrina alkaloid 3-demethoxyerythratidinone. The natural product is assembled in six steps from commercial precursors in 30–35 % overall yield and with only two chromatographical purification operations. The key step is a titanium(III) catalyzed umpolung reaction in form of a reductive imine–nitrile coupling that can be combined with a subsequent cyclization reaction on a 50 mmol scale. Furthermore, optimized Wacker oxidation conditions enable the selective alkene oxidation in the presence of a tertiary amine functionality, which has been a problem in previous syntheses of erythrina alkaloids. The racemic route can be used to prepare the natural product on gram scale and the results may be useful for the synthesis of related alkaloids.
- Luu, Hieu-Trinh,Streuff, Jan
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p. 139 - 149
(2019/01/04)
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- Synthetic method of nitrile compounds containing siloxane group
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A synthetic method of nitrile compounds containing siloxane group belongs to the technical field of battery electrolytes; OH-(CH2)n-CN and a component shown in the description are used as raw materials, wherein n is >/=2, R is selected from methyl, vinyl or tert-butyl; the synthetic method comprises the steps of A, mixing OH-(CH2)n-CN with triethylamine, stirring, and cooling to 0 DEG C to obtaina mixed solution; B, controlling the temperature at 0 DEG C, adding the component into diethyl ether, magnetically stirring for 10-15 min, adding the mixed solution of step A, stirring, ending the reaction until the component is not detected, filtering, distilling in vacuum, and drying to obtain nitrile compounds containing siloxane group. The synthetic method is simple; the obtained nitrile compounds containing siloxane group have high yield and purity and little water.
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Paragraph 0040-0045
(2018/10/11)
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- A Titanium(III)-Catalyzed Reductive Umpolung Reaction for the Synthesis of 1,1-Disubstituted Tetrahydroisoquinolines
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A catalytic reductive C1-acylation of 3,4-dihydroisoquinolines is presented that gives direct access to 1,1-disubstituted tetrahydroisoquinolines. The reaction is a titanium(III)-catalyzed reductive umpolung process in which nitriles act as effective acylation agents. The method is highly chemo- and regioselective and is demonstrated in 20 examples. It is well-suited for the large-scale synthesis of functionalized tetrahydroisoquinoline products, which is exemplified in the form of a six-step synthesis of (±)-3-demethoxyerythratidinone. (Figure Presented).
- Luu, Hieu-Trinh,Wiesler, Stefan,Frey, Georg,Streuff, Jan
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supporting information
p. 2478 - 2481
(2015/05/27)
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- Synthesis of unsaturated phosphatidylinositol 4-phosphates and the effects of substrate unsaturation on SopB phosphatase activity
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In this paper evidence is presented that the fatty acid component of an inositide substrate affects the kinetic parameters of the lipid phosphatase Salmonella Outer Protein B (SopB). A succinct route was used to prepare the naturally occurring enantiomer of phosphatidylinositol 4-phosphate (PI-4-P) with saturated, as well as singly, triply and quadruply unsaturated, fatty acid esters, in four stages: (1) The enantiomers of 2,3:5,6-O-dicyclohexylidene-myo-inositol were resolved by crystallisation of their di(acetylmandelate) diastereoisomers. (2) The resulting diol was phosphorylated regio-selectively exclusively on the 1-O using the new reagent tri(2-cyanoethyl)phosphite. (3) With the 4-OH still unprotected, the glyceride was coupled using phosphate tri-ester methodology. (4) A final phosphorylation of the 4-O, followed by global deprotection under basic then acidic conditions, provided PI-4-P bearing a range of sn-1-stearoyl, sn-2-stearoyl, -oleoyl, -γ-linolenoyl and arachidonoyl, glycerides. Enzymological studies showed that the introduction of cis-unsaturated bonds has a measurable influence on the activity (relative Vmax) of SopB. Mono-unsaturated PI-4-P exhibited a five-fold higher activity, with a two-fold higher KM, over the saturated substrate, when presented in DOPC vesicles. Poly-unsaturated PI-4-P showed little further change with respect to the singly unsaturated species. This result, coupled with our previous report that saturated PI-4-P has much higher stored curvature elastic stress than PI, supports the hypothesis that the activity of inositide phosphatase SopB has a physical role in vivo. This journal is
- Furse, Samuel,Mak, Lokhang,Tate, Edward W.,Templer, Richard H.,Ces, Oscar,Woscholski, Rüdiger,Gaffney, Piers R. J.
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supporting information
p. 2001 - 2011
(2015/03/05)
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- New approach to the synthesis of phosphorodichloridites, phosphorochloridites, and trialkyl phosphites
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Different trivalent organophosphorus esters such as phosphorodichloridites, phosphorochloridites, and mixed trialkyl phosphites have been easily synthesized in good yields using a HCl-catalyzed reaction of the corresponding chlorophosphine and alkoxytrimethylsilane by mutual exchange of the alkoxy and chlorine ligand pIIICl/ROSiR′3; exchange reaction). Chemoselectivity of the exchange reaction with primary and secondary alkoxytrimethylsilanes, as well as with alkoxytrimethylsilanes and thioalkoxytrimethylsilanes, respectively, has also been examined. It has been also found that the substitution reaction of chlorophosphines with secondary amine occurs more rapidly than the exchange reaction with ROSiR′ 3.
- Majewski, Piotr
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experimental part
p. 942 - 955
(2010/01/17)
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- Facile method for trimethylsilylation of alcohols using hexamethyldisilazane and ammonium thiocyanate under neutral conditions
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A highly efficient method for trimethylsilylation of primary, secondary, tertiary, allylic, and a variety of sugar-derived alcohols using hexamethyldisilazane in the presence of a catalytic amount of ammonium thiocyanate under neutral conditions is reported. Copyright Taylor & Francis Group, LLC.
- Jadhav, Vrushali H.,Kumar, K. S. Ajish,Chaudhari, Vinod D.,Dhavale, Dilip D.
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p. 1363 - 1370
(2008/02/01)
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- Process for manufacturing purified phosphorodiamidite
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A scalable process for purification of phosphorodiamidite includes steps of solubilizing a crude phosphorodiamidite in an apolar organic solvent, contacting the non-polar organic solvent with a polar phase comprising a polar organic solvent to remove impurities from the solubilized phosphorodiamidite, and removing the non-polar organic solvent from the phosphorodiamidite.
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- Synthesis of naturally occurring phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] and its diastereoisomers
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The chemical synthesis of naturally occurring phosphatidylinositol 3,4,5-triphosphate [PtdIns(3,4,5)P3] and its diastereoisomers was discussed. In the first stage, the preparation of the required enantiomeric 1,2-di-O-acylglycerol derivatives was done. The second stage involved the preparation of suitably protected enantiomeric myo-inositol 1-phosphates. The glycerol and inositol building blocks were coupled together and the 3-, 4- and 5-hydroxy functions of the inositol residues in the coupled products were phosphorylated. Finally, the protecting groups were removed to give PtdIns(3,4,5)P3 and its diastereoisomers.
- Gaffney, Piers R.J.,Reese, Colin B.
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p. 192 - 205
(2007/10/03)
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- Use of the 1-(2-Fluorophenyl)-4-methoxypiperidin-4-yl (Fpmp) Protecting Group in the Solid-Phase Synthesis of Oligo- and Poly-ribonucleotides
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An approach to the solid-phase synthesis of oligo- and poly-ribonucleotides is described.The synthetic strategy involves the use of building blocks in which two acid-labile groups, 1-(2-fluorophenyl)-4-methoxypiperidin-4-yl (Fpmp) and 9-phenylxanthen-9-yl
- Rao, M. Vaman,Reese, Colin B.,Schehlmann, Volker,Yu, Pak Sang
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- Reaction of Cyanotrimethylsilane with Oxiranes. Effect of Catalysts or Mediators on Regioselectivity and Ambident Character
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Reaction of cyanotrimethylsilane with oxiranes under the catalytic action of Lewis acids Pd(CN)2, SnCl2, or Me3Ga affords 2-trimethylsiloxy isocyanides by regio- and stereoselective attack of isocyanide on the more substituted carbon.The reaction mediated by aluminium alkoxides gives predominantly 3-trimethylsiloxy nitriles by the selective attack of cyanide on the less substituted carbon.
- Imi, Katsuharu,Yanagihara, Naoto,Utimoto, Kiitiro
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p. 1013 - 1016
(2007/10/02)
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