5369-62-0Relevant academic research and scientific papers
PTERIN DERIVATIVE OR SALT THEREOF
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Paragraph 0064, (2017/07/23)
PROBLEM TO BE SOLVED: To provide a compound having nitrogen monooxide production promoting effect, blood vessel protecting effect, trace quantity albumin urine suppressing effect or the like superior to tetrahydrobiopterin (BH4), for compensating reduction of nitrogen monoxide productive function due to production reduction of BH4 in diabetes. SOLUTION: There is provided a pterin derivative represented by the formula (1) or a salt thereof. (1), where R1 is a specific linear/branched alkyl group, a cycloalkyl group, a cycloalkyl-alkyl group, an aryl group, an aralkyl group, a heterocyclic specific alkyl group or -CH(OH)CH3; R2 is absent, or H or a specific linear/branched alkyl group; R3 to R5 are each independently H or a single bond; R6 and R7 are each independently H or an aryl-alkyl group, a hydroxyalkyl group or an alkoxyalkyl group. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
Asymmetric epoxidation of α,β-unsaturated aldehydes catalyzed by a spiro-pyrrolidine-derived organocatalyst
Xu, Ming-Hui,Tu, Yong-Qiang,Tian, Jin-Miao,Zhang, Fu-Min,Wang, Shao-Hua,Zhang, Shi-Heng,Zhang, Xiao-Ming
supporting information, p. 294 - 300 (2017/03/01)
The asymmetric epoxidation of α,β-unsaturated aldehydes, catalyzed by a spiro-pyrrolidine (SPD)-derived organocatalyst, has been accomplished with good diastereoselectivities (up to dr >20:1) and with high to excellent enantioselectivities (up to 99% ee).
Fluorinated organocatalysts for the enantioselective epoxidation of enals: Molecular preorganisation by the fluorine-iminium ion Gauche effect
Tanzer, Eva-Maria,Zimmer, Lucie E.,Schweizer, W. Bernd,Gilmour, Ryan
supporting information, p. 11334 - 11342,9 (2020/08/31)
The fluorine-iminium ion gauche effect is triggered upon union of a secondary β-fluoroamine and an α,β-unsaturated aldehyde, providing a useful strategy for controlling the molecular topology of intermediates that are central to organocatalytic processes. The β-fluoroamine (S)-2-(fluorodiphenylmethyl)pyrrolidine (1) is an effective catalyst for the enantioselective epoxidation of α,β-unsaturated aldehydes. A process of structural editing has revealed that the efficiency of this catalyst is due to the (fluorodiphenyl)methyl group when it is embedded in a β-fluoroiminium motif. Epoxidations of challenging cyclic α,β-disubstituted, β,β-disubstituted and α,β,β-trisubstituted enals catalysed by 1 proceed with excellent levels of enantiocontrol (up to 98 % ee). Fluorine finesse. The β-fluoroamine (S)-2-(fluorodiphenylmethyl)pyrrolidine (1) is an effective catalyst for the enantioselective epoxidation of α,β-unsaturated aldehydes (see scheme). Application of this catalyst to challenging cyclic α,β-disubstituted enals, β,β-disubstituted enals, and an α,β,β-trisubstituted enal proceeds in a highly enantioselective fashion (up to 98 % ee). Copyright
Ring-opening hydrofluorination of 2,3- and 3,4-epoxy amines by HBF 4·OEt2: Application to the asymmetric synthesis of (S, S)-3-deoxy-3-fluorosafingol
Cresswell, Alexander J.,Davies, Stephen G.,Lee, James A.,Morris, Melloney J.,Roberts, Paul M.,Thomson, James E.
experimental part, p. 4617 - 4627 (2011/07/30)
Treatment of a range of 2,3- and 3,4-epoxy amines with HBF 4·OEt2 at room temperature results in fast and efficient SN2-type ring-opening hydrofluorination to give stereodefined amino fluorohydrins. Operational simplicity, scalability, and short reaction time at ambient temperature are notable features of this method. The utility of this methodology is exemplified in a concise asymmetric synthesis of (S,S)-3-deoxy-3-fluorosafingol.
Diastereo- and enantioselective synthesis of functionalized β-lactams from oxiranecarbaldimines and lithium ester enolates
Michel, Kristin,Froehlich, Roland,Wuerthwein, Ernst-Ulrich
scheme or table, p. 5653 - 5665 (2010/03/03)
The addition of nucleophiles like lithium ester enolates 6 to oxiranecarbaldimines 1 leads to new oxiranyl-functionalised β-lactams 7 in excellent enantio- and diastereoselectivity. A simple one-pot procedure affords β-lactams (azetidin-2-ones) with three or four neighbouring stereogenic centres and unlike preference. Products resulting from oxirane ring-opening reactions were not observed. An enantiomerically enriched example (2S,3S)-1g gave the corresponding β-lactam (S,S,R)-7f in excellent enantiomeric excess. According to quantum chemical calculations the observed diastereoselectivity is the result of a diastereofacial differentiation of the two faces of the iminic double bond in the transition state.
Asymmetric counteranion-directed catalysis for the epoxidation of enals
Wang, Xingwang,List, Benjamin
, p. 1119 - 1122 (2008/09/21)
(Chemical Equation Presented) A new mode of chiral anion catalysis: A powerful chiral-counteranion strategy for catalytic asymmetric epoxidations using the newly discovered catalyst 1 has been applied to the epoxidation of α,β-unsaturated aldehydes together with tert-butyl hydroperoxide as the oxidant (see scheme). Remarkably, this system provides the corresponding epoxides in high diastereo- and enantioselectivity for both di- and trisubstituted enals.
A comparison of intrazeolite and solution singlet oxygen ene reactions of allylic alcohols
Clennan, Edward L.,Zhang, Dong,Singleton, Jamie
, p. 1226 - 1232 (2008/02/09)
The singlet oxygen ene reactions of four allylic alcohols and for comparison an allylic ether have been examined both in solution and in zeolite Y. Bronsted acid sites in the zeolite were shown to induce decomposition of several of the allylic alcohols. Treatment of the zeolites with pyridine removed these acid sites and allowed intrazeolite reactions of the allylic alcohols without interference from decomposition. Control reactions with an allylic alcohol that is inert to decomposition provided evidence that the presence of pyridine in the zeolite labyrinth does not influence the product composition.
Diastereoselective one-step synthesis of functionalized cis-aziridinyl alcohols from oxiranyl carbaldimines
Bilke, Julia Luzia,Dzuganova, Monika,Froehlich, Roland,Wuerthwein, Ernst-Ulrich
, p. 3267 - 3270 (2007/10/03)
(Chemical Equation Presented) Upon treatment with lithiumorganic nucleophiles, trans-configured oxiranyl carbaldimines are transformed into anti-configured cis-aziridinyl alcohols with excellent diastereoselectivity. This conversion may be explained by a new type of the aza-Payne rearrangement, including first a nucleophilic attack on the imine carbon atom with diastereofacial differentiation followed by an intramolecular nucleophilic opening of the oxiranyl ring with simultaneous formation of the aziridine ring.
An expeditious enantioselective synthesis of methyl trans-chrysanthemate
Krief, Alain,Dumont, Willy,Baillieul, Diane
, p. 2019 - 2022 (2007/10/03)
Methyl trans-chrysanthemate has been prepared in few steps from isopropylidenediphenylsulfurane and methyl (E)-3-(3,3-dimethyloxiran-2-yl)prop-2-enoate. The latter was obtained from methyl 4-oxobutenoate or 3-methylbut-2-en-1-ol. The Sharpless catalytic epoxidation reaction allows an asymmetric version of this transformation.
Properties of Ti-beta zeolites synthesized by dry-gel conversion and hydrothermal methods
Tatsumi, Takashi,Jappar, Nizamidin
, p. 7126 - 7131 (2007/10/03)
The large-pore beta zeolite containing Ti has been synthesized in the presence of alkali cations (Na+) by a dry-gel conversion (DGC) technique using tetraethylammonium hydroxide (TEAOH) as a structure-directing agent. The obtained Ti-beta zeolites were compared with hydrothermally synthesized (HTS) Ti-beta. It was found that Ti-beta-DGC samples adsorbed less water (12-13 wt %) than Ti-beta-HTS (19 wt %), indicating that Ti-beta-DGC is more hydrophobic than Ti-beta-HTS. We propose that this leads to a higher activity for the former in the oxidation of cyclohexane. Upon being washed with H2SO4, the turnover number (TON) of DGC samples slightly increased for the oxidation of cyclohexane. DGC and HTS samples demonstrated no significant difference in the activity for oxidation reactions of unsaturated alcohols and C6-C8 cyclic alcohols.
