15761-38-3Relevant articles and documents
Optically active helical substituted polyacetylenes as chiral seeding for inducing enantioselective crystallization of racemic N -(tert -butoxycarbonyl)alanine
Chen, Bo,Deng, Jianping,Cui, Xin,Yang, Wantai
, p. 7109 - 7114 (2011)
Helical substituted polyacetylenes were investigated for inducing enantioselective crystallization of racemic N-(tert-butoxycarbonyl)alanine (BOC-alanine) enantiomers. For this purpose, helical substituted polyacetylenes [(R)-PSA and (S)-PSA)] were dissolved in supersaturated racemic BOC-alanine solutions. Upon cooling the solutions, (R)-PSA preferentially induced BOC-l-alanine to crystallize, while (S)-PSA facilitated the enantioselective crystallization of BOC-d-alanine, according to the characterizations by circular dichroism, XRD, SEM, and optical rotation analyses. As expected, no enantioselective crystallization was observed in such cases: racemic BOC-alanine enantiomers in the absence of optically active helical PSA and racemic BOC-alanine enantiomers in the presence of equal amount of (R)-PSA and (S)-PSA. The present study provides the first direct evidence for the role of artificially synthetic helical polymers in inducing efficiently enantioselective crystallization.
Synthesis and biological properties of enkephalin-like peptides containing carboranylalanine in place of phenylalanine
Schwyzer,Do,Eberle,Fauchere
, p. 2078 - 2083 (1981)
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Copolymerization of chiral amino acid-based acetylenes and helical conformation of the copolymers
Gao, Guangzheng,Sanda, Fumio,Masuda, Toshio
, p. 3938 - 3943 (2003)
The present study deals with the copolymerization of an amino acid-based acetylene, N-(tert-butoxycarbonyl)-L-alanine N′-propargylamide (L-1A) with the optical isomer (D-1A), achiral hexanoic acid N-propargylamide (2A), and pivalic acid N-propargylamide (3A), and chiroptical properties of the copolymers. The copolymerization catalyzed by (nbd)Rh+[η6-C6H5B- (C6H5)3] afforded copolymers with number-average molecular weights over 104 in good yields. Nonlinear relationships were observed in the specific rotation and CD and UV-vis spectroscopies with respect to the L-1A content in feed. For instance, poly(L-1A-co-D-1A)s incorporated with 12.5% of either optical isomer (75% ee) exhibited almost the same optical properties as those of the homopolymers. Chiral amplification was observed in the copolymerization of L-1A with the achiral monomers. The specific rotation of poly(L-1A-co-2A) with 45% L-1A unit was practically the same as that of poly(L-1A). The copolymers of L-1A and 3A with an L-1A content in feed as low as 12% exhibited nearly the same helix content as the homopolymer of L-1A did.
Efficient, non-acidolytic method for the selective cleavage of N-Boc amino acid and peptide phenacyl esters linked to a polystyrene resin
Furlan, Ricardo L. E.,Mata, Ernesto G.,Mascaretti, Oreste A.
, p. 355 - 358 (1998)
An efficient, non-acidolytic method for the selective cleavage of phenacyl esters of N-Boc-amino acids and -peptides linked to a polystyrene resin by (CH3)3SnOH (TMTOH) or [(n-C4H9)3Sn]2O (BBTO) is described. We highly recommend the use of trimethyltin hydroxide for the selective cleavage of carboxylic esters based on its favourable properties. The method is compatible with an N-Boc/O-Bn (benzyl ether) strategy and yields enantiomerically pure N-Boc-peptides useful for further manipulation, for segment condensations or for cyclization strategies. A mechanism for the cleavage of methyl phenylacetate in solution by TMTOH is postulated.
Biocatalytic resolution of Boc-dl-alanine methyl ester by a newly isolated Bacillus amyloliquefaciens WZZ002
Zheng, Jian-Yong,Wang, Yu-Qiang,Luo, Wei-Feng,Zhou, Sha-Sha,Zhu, Qing,Ying, Xiang-Xian,Wang, Zhao
, p. 134 - 137 (2014)
A new esterase-producing strain (Bacillus amyloliquefaciens WZZ002) that exhibits high hydrolytic activity, excellent enantioselectivity, and high substrate tolerance on Boc-dl-Alanine methyl ester was isolated from soil samples. The reaction temperature, pH, and neutralizer optima of the cell-mediated biocatalysis were 35 °C, pH 8.0, and NH3·H2O, respectively. The optimal substrate concentration was 2 M, with a biocatalyst loading of 50 g/L. Results showed that the enantiomeric excess values of substrate and product were both greater than 99%. Thus, bioprocessing with the use of the isolated strain is a promising route for the commercial production of Boc-d-Ala-OMe.
Self-assembly of β-turn forming synthetic tripeptides into supramolecular β-sheets and amyloid-like fibrils in the solid state
Maji, Samir Kumar,Haldar, Debasish,Drew, Michael G. B.,Banerjee, Arijit,Das, Apurba Kumar,Banerjee, Arindam
, p. 3251 - 3259 (2004)
We have described here the self-assembling properties of the synthetic tripeptides Boc-Ala(1)-Aib(2)-Val(3)-OMe 1, Boc-Ala(1)-Aib(2)-Ile(3)-OMe 2 and Boc-Ala(1)-Gly(2)-Val(3)-OMe 3 (Aib=α-amino isobutyric acid, β-Ala=β-alanine) which have distorted β-turn conformations in their respective crystals. These turn-forming tripeptides self-assemble to form supramolecular β-sheet structures through intermolecular hydrogen bonding and other noncovalent interactions. The scanning electron micrographs of these peptides revealed that these compounds form amyloid-like fibrils, the causative factor for many neurodegenerative diseases including Alzheimer's disease, Huntington's disease and Prion-related encephalopathies.
Enantioselective hydrolysis of amino acid esters by non-chiral copper complexes equipped with bis (β-cyclodextrin)s
Xue, Shan-Shan,Zhao, Meng,Lan, Jing-Xing,Ye, Rui-Rong,Li, Yi,Ji, Liang-Nian,Mao, Zong-Wan
, p. 297 - 303 (2016)
Two non-chiral copper(II) complexes equipped with bis(β-cyclodextrin)s (bisCDs) were explored as hydrolase models for the enantioselective hydrolysis of two pairs of alkyl chain-possessing amino acid ester enantiomers. The two bisCD complexes are pyridine-linked with different CD cavity orientations, denoted as CuL1 (L1?=?2,6-bis(6-mono-amino-β-cyclodextrin-methyl)-pyridine) and CuL2 (L2?=?2,6-bis(3-mono-amino-β-cyclodextrin-methyl)-pyridine). Kinetic studies indicated that the “back-to-back” bisCD complex CuL1 showed higher catalytic efficiency and more pronounced enantioselectivity for all substrates than the “face-to-face” bisCD complex CuL2. Overall preference of L-isomers was observed for both complexes. In the presence of CuL1, the formation of catalyst-substrate Michaelis complexes during the hydrolysis was demonstrated by saturation kinetic study and Electrospray ionization mass spectrometry (ESI–MS) analysis. Enantiomer selectivity (vmaxL/vmaxD) value for N-Boc-N'-Boc-Lysine 4-nitrophenyl esters (Boc-Lys(Boc)-ONp), the longer alkyl-chain analogs, is twice of that for N-Boc-Alanine 4-nitrophenyl esters (Boc-Ala-ONp). The enantioselective hydrolysis of Boc-Lys(Boc)-ONp promoted by CuL1 was confirmed by chiral high-performance liquid chromatography (HPLC) analysis. The participation of CD cavities during enantioselective hydrolysis was investigated through inhibition assay. The enantioselectivity in hydrolyzing different amino acid esters promoted by CuL1 was compared. The mechanism involved in the cooperation of two adjacent CD cavities of bisCD was proposed.
Monofunctional platinum complexes showing potent cytotoxicity against human liver carcinoma cell line BEL-7402
Zhang, Junyong,Wang, Xiaoyong,Tu, Chao,Lin, Jun,Ding, Jian,Lin, Liping,Wang, Zheming,He, Cheng,Yan, Chunhua,You, Xiaozeng,Guo, Zijian
, p. 3502 - 3507 (2003)
Three novel Pt(II) complexes [PtL1′Cl] I (L1′ = glycine-N′-8-quinolylamide), [PtL2′Cl] II (L2′= L-alanine-N′-8-quinolylamide), and [PtL3Cl] III [L3 = N-(tert-butoxycarbonyl)-L-methionine-N′-8-quinolylamide] have been synthesized and characterized. The crystal structure of complexes II and III showed that the ligands are three-coordinated with only one Cl- as the leaving group. Complex II crystallized in the monoclinic system with space group P2(1), a = 9.502(2) ?, b = 4.724(1) ?, c = 14.800(3) ?, while complex III crystallized in the orthorhombic system with space group P2(1)2(1)2(1), a = 5.441(1) ?, b = 12.978(3) ?, c = 29.438(6) ?. These complexes have been tested against a wide range of tumor cell lines including BEL-7402, HCT-116, SPC-A4, MOLT-4, P388, HL-60, A-549, SGC-7901, MKN-28, and HO-8910. Complex III is highly cytotoxic against the HCT-116 (IC50 = 0.38 μM), SPC-A4 (IC50 = 0.43 μM), BEL-7402 (IC50 = 0.43 μM), and MOLT-4 (IC50 = 0.61 μM) cell lines. The cell line most sensitive to III is human liver carcinoma cell line BEL-7402, which has a response rate of 75.1% at 6.6 × 10-7 M, nearly 6 times higher than that of cisplatin.
Membrane transport inspired hydrolysis of non-activated esters at near physiological pH
Mandal, Raki,Mahanty, Kingshuk,Mandal, Subhendu,De Sarkar, Suman,Tarafdar, Pradip K.
supporting information, p. 11088 - 11091 (2021/10/30)
A positively charged micelle loaded with substrates was transported selectively to the reaction site (cathode) to promote the proximity and localization of the reactants (ester and hydroxide). The guided vehicular delivery coupled with electrolysis allows the hydrolysis of non-activated esters at near physiological pH with significant yields along with recyclability.
Design, synthesis, and biological evaluation of novel Bcr-AblT315I inhibitors incorporating amino acids as flexible linker
Li, Yanchen,Li, Zilong,Liu, Nanxin,Pan, Xiaoyan,Shan, YuanYuan,Wang, Kai,Zhang, Jie,Zhang, Qingqing
, (2021/09/22)
Despite the success of imatinib in CML therapy through Bcr-Abl inhibition, acquired drug resistance occurs over time in patients. In particular, the resistance caused by T315I mutation remains a challenge in clinic. Herein, we embarked on a structural optimization campaign aiming at discovery of novel Bcr-Abl inhibitors toward T315I mutant based on previously reported dibenzoylpiperazin derivatives. We proposed that incorporation of flexible linker could achieve potent inhibition of Bcr-AblT315I by avoiding steric clash with bulky sidechain of Ile315. A library of 28 compounds with amino acids as linker has been developed and evaluated. Among them, compound AA2 displayed the most potent activity against Bcr-AblWT and Bcr-AblT315I, as well as toward Bcr-Abl driven K562 and K562R cells. Further investigations indicated that AA2 could induce apoptosis of K562 cells and down regulate phosphorylation of Bcr-Abl. In summary, the compounds with amino acid as novel flexible linker exhibited certain antitumor activities, providing valuable hints for the discovery of novel Bcr-Abl inhibitors to overcome T315I mutant resistance, and AA2 could be considered as a candidate for further optimization.
