4522-04-7Relevant academic research and scientific papers
Kendarimide A, a novel peptide reversing P-glycoprotein-mediated multidrug resistance in tumor cells, from a marine sponge of Haliclona sp.
Aoki, Shunji,Cao, Liwei,Matsui, Kouhei,Rachmat, Rachmaniar,Akiyama, Shin-Ichi,Kobayashi, Motomasa
, p. 7053 - 7059 (2004)
A novel modulator of multidrug resistance (MDR) in tumor cells, kendarimide A (1), was isolated from an Indonesian marine sponge of Haliclona sp. Compound 1 reversed MDR in KB-C2 cells mediated by P-glycoprotein (P-gp) at a 6 μM concentration, and the chemical structure of 1 was characterized to be a linear peptide composed of N-methylpyroglutamic acid (pyroMeGlu), N-methylated eight-membered cysteinyl-cysteine (ox-[MeCys-MeCys]) together with many N-methyl amino acid residues. The amino acid sequence of 1 was determined by 2D NMR and FAB MS analysis. The absolute configuration of the amino acid residues in 1 except for the MeCys part was determined to be L-form respectively, based on interpretation of the HPLC analysis of Marfey's derivatives of the hydrolysates of 1 and the synthetic method for the pyroMeGlu residue.
Synthesis of protected α-amino acids: Via decarboxylation amination from malonate derivatives
Dai, Qipu,Fu, Hui,Hu, Changwen,Li, Peihe,Li, Xiaoying,Wang, Zheng
, p. 4439 - 4446 (2020/10/20)
A general and efficient strategy for the synthesis of protected α-amino acids is reported. The method uses malonate derivatives as the starting materials and Cs2CO3 as a base at 60 degrees, giving α-amino acid derivatives in moderate yields by releasing CO2. This methodology shows broad substrate scope (primary and secondary acids), excellent functional group tolerance and high efficiency to give the desired products under mild reaction conditions. It also allows the construction of β and γ-amino acids and other unnatural products.
A (1 R, 3 S) -3 - amino-cyclopentanol hydrochloride preparation method (by machine translation)
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, (2019/05/08)
The invention discloses a (1 R, 3 S) - 3 - amino-cyclopentanol hydrochloride of the preparation method, the method using chiral carboxylic acid with hydroxylamine to form the amide as chiral source, in copper catalyzed oxidation in the reaction system to rapidly obtain a chiral Diels - alder reaction product, after passes through the reduction reaction and alkaline deprotection reaction, and acidified after reaction to obtain the target product. Chiral inducing reagent chiral carboxylic acid by simple acidification, extraction processing can be reclaimed and reused. This kind of (1 R, 3 S) - 3 - amino-cyclopentanol hydrochloride preparation method has high operation safety and high selectivity, raw materials are easy, and the cost is low, the reaction time is short and simple process flow and the like. (by machine translation)
Ring opening reactions of cyclic sulfamidates. Synthesis of β-fluoroaryl alanines and derivatives of 4,4-difluoroglutamic acid
Bolek, Sylwia,Ignatowska, Jolanta
, p. 13 - 21 (2018/11/24)
Ring opening reactions of 1 with copper complex formed between Cu, TMEDA and BrCF2CO2Et lead to optically active 4,4-difluoroglutamic acid derivatives 11a-d in moderate yields. Reaction of cyclic sulfamidates 1 with fluoro substituted arylmagnesium chlorides proceed via copper catalyzed 1,4-addition of Grignard reagent to dehydroalanine 2, formed in situ. Fluorinated organoznic derivatives were unreactive towards 1 regardless of the reaction conditions; instead product of reaction of 1 with DMF was isolated.
Base catalytic decarboxylation amination preparation method of amino-acid ester/amide
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Paragraph 0064-0065, (2019/10/10)
The invention discloses a base catalytic preparation method of alpha amino-acid ester/amide from beta carbonyl acid, and belongs to the field of organic chemistry. According to the method, malonate is taken as a raw material, single hydrolysis is carried out to obtain beta carbonyl acid, reaction with a hydroxylamine compound is carried out to obtain an acyloxyl carbamic acid ester, and under the effect of an alkali, removing of one molecule carbon dioxide is carried out so as to obtain an alpha amino-acid ester, wherein the process of synthesis of the alpha amino-acid ester/amide is similar to the above process. The raw materials are widely available; operation is simple and convenient; reaction conditions are mild; using of toxic cyanide and derivatives of cyanide, strong oxidizing/reducing agents, and precious metal catalysts in a conventional alpha amino acid synthesis method is avoided; and requirements of the trend of green chemistry development are satisfied.
Diastereoselective Synthesis of Unnatural Amino Acids by Alkylation of α- Tert-Butanesulfinamide Auxiliary-Bound Enolates
Dwulet, Natalie C.,Zolfaghari, Tina A.,Brown, Molly L.,Cannon, Jeffrey S.
, p. 11510 - 11518 (2018/09/27)
A new chiral auxiliary for the diastereoselective alkylation of amino ester enolates that takes advantage of chiral information stored on the enolate side of the amino ester substrate has been developed. Chiral α-sulfinamido esters were alkylated under basic conditions in good yields (up to 90%) and good to high diastereoselectivities (generally >6:1) to provide unnatural mono- and α,α-disubstituted amino acid derivatives. This auxiliary allowed for the ready conversion of ester functionality without the need for esoteric reagents. Furthermore, the auxiliary is easily removed to provide enantiopure amino acids. Computational studies revealed that a chelated transition state governs electrophile addition from the convex face of a transient bicyclic intermediate. This method allows ready access to enantioenriched natural and unnatural amino acids.
Copper nanoparticles catalyzed N-H functionalization: An efficient solvent-free N-tert-butyloxycarbonylation strategy
Deb, Barnali,Debnath, Sudipto,Deb, Anindita,Maiti, Dilip K.,Majumdar, Swapan
supporting information, p. 629 - 633 (2017/01/25)
A chemoselective transformation of amines to their tert-butyloxycarbonyl (Boc) protected derivatives (NBoc) is described using Cu-NPs under solvent-free conditions. Simple method, rapid reaction rate, mild conditions, tolerance of a wide range of functional groups, excellent yield, ease recovery and high catalytic turnover are the salient features of this approach. tert-Butyloxycarbonylation of chiral amino acid esters and amino alcohols were performed without racemization.
Towards a universal organocatalyst for the synthesis of enantioenriched phenylalanine derivatives by enantioselective decarboxylative protonation
Pigeaux, Morgane,Laporte, Romain,Harrowven, David C.,Baudoux, Jér?me,Rouden, Jacques
, p. 4599 - 4603 (2016/09/23)
Access to enantioenriched non-proteogenic phenylalanine derivatives is described using the enantioselective decarboxylative protonation reaction of amidohemimalonate esters catalysed by various cinchona-based compounds. This study compares the catalytic efficiency as well as the enantioselectivity induced by three types of common organocatalysts, namely thioureas, squaramides and bis-cinchona squaramides. One of the main outcome of this work is the observation of a significant influence of the N-protecting group of the hemimalonate on its interaction with the catalyst. This methodology carried out under mild conditions exhibits good substrate scope and functional group tolerance. A substoichiometric amount of catalyst can also be used in certain cases while affording good yields and selectivities.
Non-noble metal-based catalytic of high-efficiency oxidation coupling reaction C-H/C-H preparing β-(hetero) aryl propionic acid derivatives
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Paragraph 0029; 0031, (2017/03/24)
The invention relates to a method for efficiently preparing beta-(hybrid)aryl alanine derivative based on non-noble metal catalyzed C-H/C-H oxidative coupling action. Aiming at the defects of the prior art, the invention provides the preparation method of beta-(hybrid)aryl alanine derivative. The preparation method is simpler, more efficient and environmentally friendly than the traditional method, adopts non-noble metal catalysis, adopts alpha-amino acid derivative and (hybrid)aryl methane derivative as starting materials, adopts a mild organic oxidizer, and avoids the using of noble metal salt and strong base, thereby being capable of greatly reducing the cost, synthesis procedures, operation difficulty, hazardous waste and equipment corrosion, and having a good industrial production prospect.
Selective esterifications of primary alcohols in a water-containing solvent
Wang, Yong,Aleiwi, Bilal A.,Wang, Qinghui,Kurosu, Michio
supporting information, p. 4910 - 4913,4 (2012/12/12)
Oxyma and an oxyma derivative, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-cyano-2-(hydroxyimino)acetate (5b), displayed a remarkable effect on selective esterifications of primary alcohols. A wide range of carboxylic acids could be esterified with primary alcohols by using EDCI, NaHCO3, and Oxyma or Oxyma derivative 5b in 5% H2O-CH3CN. Oxyma derivative 5b is particularly useful, since it could be removed after the reaction via a simple basic or an acidic aqueous workup procedure.
