199588-89-1Relevant articles and documents
Methylene Analogues of Neopetrosiamide as Potential Antimetastatic Agents: Solid-Supported Syntheses Using Diamino Diacids for Pre-Stapling of Peptides with Multiple Disulfides
Engelhardt, Daniel B.,Pascoe, Cameron A.,Rosana, Albert Remus R.,Van Belkum, Marco J.,Vederas, John C.
supporting information, p. 9216 - 9220 (2021/11/30)
Neopetrosiamide, a 28-residue peptide from Neopetrosia sp., contains three disulfide bonds and hinders mammalian tumor cell invasion. Proper connectivity of disulfide bonds is crucial for activity. Synthetic replacement of single disulfide bridges with methylene bridges gives active analogues. Pre-stapling of one ring enhances the correct formation of the remaining disulfides by reducing isomeric possibilities and possibly initiating the correct 3D fold. Cloning and expression of neopetrosiamide in E. coli affords access to the natural linear peptide.
A Unified Approach to Phytosiderophore Natural Products
Kratena, Nicolas,G?kler, Tobias,Maltrovsky, Lara,Oburger, Eva,Stanetty, Christian
supporting information, p. 577 - 580 (2020/11/02)
This work reports on the concise total synthesis of eight natural products of the mugineic acid and avenic acid families (phytosiderophores). An innovative ?east-to-west“ assembly of the trimeric products resulted in a high degree of divergence enabling the formation of the final products in just 10 or 11 steps each with a minimum of overall synthetic effort. Chiral pool starting materials (l-malic acid, threonines) were employed for the outer building blocks while the middle building blocks were accessed by diastereo- and enantioselective methods. A highlight of this work consists in the straightforward preparation of epimeric hydroxyazetidine amino acids, useful building blocks on their own, enabling the first synthesis of 3’’-hydroxymugineic acid and 3’’-hydroxy-2’-deoxymugineic acid.
Pd/Cu dual catalysis: Highly enantioselective access to α-substituted α-amino acids and α-amino amides
Huo, Xiaohong,Fu, Jingke,He, Xiaobo,Chen, Jianzhong,Xie, Fang,Zhang, Wanbin
supporting information, p. 599 - 602 (2018/02/06)
The asymmetric allylation of glycine iminoesters has been accomplished through a synergistic Pd/Cu catalyst system, affording a range of α-substituted α-amino acids in high yields and with excellent enantioselectivities (88 → 99% ee). The introduction of a Cu-P,N-metallocenyl complex-activated glycine iminoester to the chiral palladium-catalyzed allylic allylation process is crucial owing to its high reactivity and excellent enantioselectivities. Importantly, this Pd/Cu dual catalysis strategy can be used for the asymmetric allylic alkylation of prochiral glycine amide derivatives, which could be further utilized to synthesize biologically important vicinal diamines.
Recoverable Dendritic Phase-Transfer Catalysts that Contain (+)-Cinchonine-Derived Ammonium Salts
Rull, Jordi,Jara, José Juan,Sebastián, Rosa M.,Vallribera, Adelina,Nájera, Carmen,Majoral, Jean-Pierre,Caminade, Anne-Marie
, p. 2049 - 2056 (2016/07/07)
Four new phosphorus dendrimeric phase-transfer catalysts are prepared that contain 12 (+)-cinchoninium salts on the surface obtained by the quaternisation of the quinuclidinic N atom. The asymmetric alkylation of a glycinate Schiff base with benzyl bromide is used as a benchmark reaction, and the dendrimeric catalyst that contains an allyl group on the O-9 hydroxy group of the cinchonine units is the most active. The recovery and reuse of the catalyst are possible for five consecutive runs without loss of activity and with only a slight decrease in enantioselectivity. If other electrophiles are used, substituted benzyl bromides give better results than other activated alkyl bromides to afford the corresponding R amino acid derivatives. A comparison of these results with those reported previously for similar cinchoninium salts shows that dendrimers could be a better support than other polymers for this type of organocatalysis.
Substrate stereocontrol in the intramolecular organocatalyzed tsuji-trost reaction: Enantioselective synthesis of allokainates
Vulovic, Bojan,Gruden-Pavlovic, Maja,Matovic, Radomir,Saicic, Radomir N.
supporting information, p. 34 - 37 (2014/01/23)
Organocatalyzed Tsuji-Trost cyclization of 3b proceeds with asymmetric induction and allows for stereoselective synthesis of (+)-allokainic acid. The stereochemical outcome of the cyclization was predicted by calculations.
Total synthesis and absolute configuration of the natural amino acid tetrahydrolathyrine
Benohoud, Meryem,Leman, Loic,Cardoso, Silvia H.,Retailleau, Pascal,Dauban, Philippe,Thierry, Josiane,Dodd, Robert H.
supporting information; experimental part, p. 5331 - 5336 (2009/12/03)
(Chemical Equation Presented) The natural product tetrahydrolathyrine has been synthesized through an iminoiodane-mediated aziridination of a (2S)-allylglycinol derivative, which provided a 2:3 mixture of diastereoisomers. One of these diastereoisomers wa
PROCESS FOR PRODUCTION OF MONO-SUBSTITUTED ALKYLATED COMPOUND USING ALDIMINE OR DERIVATIVE THEREOF
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Page/Page column 106-107, (2008/06/13)
Disclosed is a process for producing an asymmetric mono-substituted alkylated compound of an α-amino acid which is represented by a specific formula by using an aldimine-type Schiff base. In the process, the alkylation of an aldimine-type Schiff base in a medium in the presence of an optically active quaternary ammonium salt phase transfer catalyst and an inorganic base is started, and subsequently the reaction is quenched at any time preceding the completion of the stoichimetrical reaction, thereby yielding a mono-substituted alkylated product having a high optical purity.
Highly enantioselective monoalkylation of p-chlorobenzaldehyde imine of glycine tert-butyl ester under mild phase-transfer conditions
Ooi, Takashi,Arimura, Yuichiro,Hiraiwa, Yukihiro,Yuan, Lin Ming,Kano, Taichi,Inoue, Toru,Matsumoto, Jun,Maruoka, Keiji
, p. 603 - 606 (2007/10/03)
The selective monoalkylation of glycine tert-butyl ester aldimine Schiff base 3 has been realized in high chemical yield with excellent enantioselectivity under mild liquid-liquid phase-transfer conditions by the use of binaphthyl-derived chiral quaternar
Diastereoselective isothiourea iodocyclization for manzacidin synthesis
Woo, Jacqueline C.S.,MacKay, D. Bruce
, p. 2881 - 2883 (2007/10/03)
We have devised a novel strategy for the total synthesis of the manzacidins. Our approach utilizes an isothiourea iodocyclization strategy to directly form the heterocyclic core, and in the process induce stereoselectivity at the quaternary center. We have found that cyclization can be achieved using an isothiourea as the nucleophilic partner. Cyclization proceeds smoothly using IBr at low temperature, affording an advanced intermediate along our proposed route to manzacidin A in 92% yield. We have demonstrated the scope of the reaction by preparing several cyclic isothioureas, including an intermediate on our proposed route for the synthesis of manzacidin D.
Evaluation of the Efficiency of the Chiral Quaternary Ammonium Salt β-Np-NAS-Br in the Organic-Aqueous Phase-Transfer Alkylation of a Protected Glycine Derivative
Ooi, Takashi,Uematsu, Yukitaka,Maruoka, Keiji
, p. 288 - 291 (2007/10/03)
The inherent efficiency of the N-spiro C2-symmetric chiral quaternary ammonium salt (S,S)-3 [(S,S)-β-Np-NAS-Br] has been evaluated in the representative organic-aqueous liquid-liquid phase-transfer benzylation and allylation of glycine tert-but
