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.
Metal-induced supramolecular chirality inversion of small self-assembled molecules in solution
Kokan, Zoran,Peri?, Berislav,Vazdar, Mario,Marini?, ?eljko,Viki?-Topi?, Dra?en,Me?trovi?, Ernest,Kirin, Sre?ko I.
, p. 1945 - 1948 (2017)
A non-covalent self-assembled chiral alanyl aminopyridine ligand exhibits supramolecular chirality in solution, independent of the organic solvent used. The supramolecular chirality of the assemblies is completely inverted by complexation to zinc ions. To date, such a supramolecular metal-ligand system has not been reported in the literature.
HIGH PRESSURE APPROACH TO THE TOTAL SYNTHESIS OF 6-EPI-D-PURPUROSAMIN B
Golebiowski, Adam,Jacobsson, Ulla,Jurczak, Janusz
, p. 3063 - 3066 (1987)
Methyl 2,6-di-N-acetyl-6-epi-α-D-purpurosaminide B (11) was synthesized from L-alanine by an eleven-step reaction sequence.Eu(fod)3-mediated high-pressure (4+2)cycloaddition of 1-methoxybuta-1,3-diene (2) to α-amino aldehyde 3, easily available from L-alanine (4), is the key step in the synthetic sequence.
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.
Pinensins: The First Antifungal Lantibiotics
Mohr, Kathrin I.,Volz, Carsten,Jansen, Rolf,Wray, Victor,Hoffmann, Judith,Bernecker, Steffen,Wink, Joachim,Gerth, Klaus,Stadler, Marc,Müller, Rolf
, p. 11254 - 11258 (2015)
Lantibiotics (lanthionine-containing antibiotics) from Gram-positive bacteria typically exhibit activity against Gram-positive bacteria. The activity and structure of pinensin A (1) and B (2), lantibiotics isolated from a native Gram-negative producer Chitinophaga pinensis are described. Surprisingly, the pinensins were found to be highly active against many filamentous fungi and yeasts but show only weak antibacterial activity. To the best of our knowledge, lantibiotic fungicides have not been described before. An in-depth bioinformatic analysis of the biosynthetic gene cluster established the ribosomal origin of these compounds and identified candidate genes encoding all of the enzymes required for post-translational modification. Additional encoded functions enabled us to build up a hypothesis for the biosynthesis, export, sensing, and import of this intriguing lantibiotic.
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.
Significant enantioselectivity in alanine ester hydrolysis catalyzed by imidazole attached β-cyclodextrins
Hamasaki, Keita,Ueno, Akihiko
, p. 859 - 860 (1995)
Imidazole-appended β-cyclodextrins, 3-deoxy-3=imidazolyl-β-cyclodextrin (3Im-βCyD) and 6-deoxy-6-imidazolyl-β-cyclodextrin (6Im-βCyD) were synthesized as substrate selective enzyme mimics. 6Im-βCyD shows marked enantioselectivity in the hydrolysis of Boc-alanine p-nitrophenyl ester rather than 3Im-βCyD.This selectivity could be interpreted by transition stability theory.
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.
Adrenocorticotropin. 48. Synthesis and biological activity of [15,16 D lysine, 17,18 D arginine] adrenocorticotropin (1 19) and an all D retropeptide related to the amino terminal octadecapeptide of adrenocorticotropin
Blake,Li
, p. 589 - 595 (1976)
The peptide [15, 16-D-lysine, 17, 18-D-arginine]-adrenocorticotropin -(1-19) and an all-D-retropeptide related to the amino terminal octadecapeptide of adrenocorticotropin have been synthesized by the solid-phase method. The nonadecapeptide was shown to p
