- Kinetic Resolution of Aromatic β-Amino Acids Using a Combination of Phenylalanine Ammonia Lyase and Aminomutase Biocatalysts
-
An enzymatic strategy for the preparation of (R)-β-arylalanines employing phenylalanine aminomutase and ammonia lyase (PAM and PAL) enzymes has been demonstrated. Candidate PAMs with the desired (S)-selectivity from Streptomyces maritimus (EncP) and Bacillus sp. (PabH) were identified via sequence analysis using a well-studied template sequence. The newly discovered PabH could be linked to the first ever proposed biosynthesis of pyloricidin-like secondary metabolites and was shown to display better β-lyase activity in many cases. In spite of this, a method combining the higher conversion of EncP with a strict α-lyase from Anabaena variabilis (AvPAL) was found to be more amenable, allowing kinetic resolution of five racemic substrates and a preparative-scale reaction with >98% (R) enantiomeric excess. This work represents an improved and enantiocomplementary method to existing biocatalytic strategies, allowing simple product separation and modular telescopic combination with a preceding chemical step using an achiral aldehyde as starting material. (Figure presented.).
- Weise, Nicholas J.,Ahmed, Syed T.,Parmeggiani, Fabio,Turner, Nicholas J.
-
supporting information
p. 1570 - 1576
(2017/05/05)
-
- The N-Hydroxymethyl Group as a Traceless Activating Group for the CAL-B-Catalysed Ring Cleavage of β-Lactams: A Type of Two-Step Cascade Reaction
-
An efficient enzymatic two-step cascade procedure has been devised for rapid access to diverse amino acids from N-hydroxymethyl-β-lactams; representative amino acids include the antifungal agent cispentacin, intermediates for the taxol side-chain, and assorted cathepsin inhibitors. When CAL-B-catalysed hydrolyses of racemic N-hydroxymethyl-β-lactams were performed with H2O (0.5 equiv.) in iPr2O at 60 °C, relatively quick (vs. non-activated counterparts) and enantioselective (E > 200) ring cleavage reactions took place. As the ring-opened amino acids formed, the hydroxymethyl group, as a traceless activating group, underwent spontaneous in situ degradation. Consequently, the desired β-amino acid and unreacted N-hydroxymethyl-β-lactam enantiomers (ee > 95 %) were formed. The formation of polymers, induced by liberation of formaldehyde, was successfully restricted by the addition of benzylamine as a capture agent, to the enzymatic reactions. An efficient enzymatic two-step cascade procedure was devised for CAL-B-catalysed hydrolysis of racemic N-hydroxymethyl-β-lactams. Conditions in which the hydroxymethyl group serves as a traceless activating group (E > 200), giving desired β-amino acid along with unreacted starting lactam enantiomers (ee > 95 %) were identified; polymerization was controlled by addition benzylamine addition.
- Forró, Enik?,Galla, Zsolt,Fül?p, Ferenc
-
p. 2647 - 2652
(2016/06/09)
-
- The bacterial ammonia lyase EncP: A tunable biocatalyst for the synthesis of unnatural amino acids
-
Enzymes of the class I lyase-like family catalyze the asymmetric addition of ammonia to arylacrylates, yielding high value amino acids as products. Recent examples include the use of phenylalanine ammonia lyases (PALs), either alone or as a gateway to deracemization cascades (giving (S)- or (R)-α-phenylalanine derivatives, respectively), and also eukaryotic phenylalanine aminomutases (PAMs) for the synthesis of the (R)-β-products. Herein, we present the investigation of another family member, EncP from Streptomyces maritimus, thereby expanding the biocatalytic toolbox and enabling the production of the missing (S)-β-isomer. EncP was found to convert a range of arylacrylates to a mixture of (S)-α- and (S)-β-arylalanines, with regioselectivity correlating to the strength of electron-withdrawing/-donating groups on the ring of each substrate. The low regioselectivity of the wild-type enzyme was addressed via structure-based rational design to generate three variants with altered preference for either α- or β-products. By examining various biocatalyst/substrate combinations, it was demonstrated that the amination pattern of the reaction could be tuned to achieve selectivities between 99:1 and 1:99 for β:α-product ratios as desired.
- Weise, Nicholas J.,Parmeggiani, Fabio,Ahmed, Syed T.,Turner, Nicholas J.
-
supporting information
p. 12977 - 12983
(2015/10/28)
-
- Enzymatic preparation of (S)-3-amino-3-(o-tolyl)propanoic acid, a key intermediate for the construction of Cathepsin inhibitors
-
Enantiomerically pure (S)-3-amino-3-(o-tolyl)propanoic acid [(S)-6], identified as the preferred enantiomeric form for the construction of novel β-amino acid derivatives as inhibitors of Cathepsin, was prepared through both indirect and direct enzymatic strategies. Resolution of hydroxymethylated β-lactam (±)-1 through Burkholderia cepacia lipase PSIM-catalysed R-selective butyrylation (E > 200) was first carried out in t-BuOMe. Treatment of the unreacted (S)-1 with 18% HCl then furnished the desired (S)-6·HCl. Next, Candida antarctica lipase B catalysed the ring cleavage of racemic 4-(o-tolyl)azetidin-2-one [(±)-2] with excellent R enantioselectivity (E > 200), either in t-BuOMe with added H2O as nucleophile or in H2O at 60 C. Hydrolysis of the less reactive β-lactam enantiomer [(S)-2] with 18% HCl afforded (S)-6·HCl. A direct enzymatic route to enantiomeric (S)-6 was finally optimized through the lipase PSIM-catalysed S-enantioselective (E > 200) hydrolysis of racemic ethyl 3-amino-3-(o-tolyl)propanoate [(±)-3] in t-BuOMe with added H 2O at 45 C or in H2O at 3 C.
- Forro, Enik,Tasnadi, Gabor,Fueloep, Ferenc
-
-
- β-styryl- and β-aryl-β-alanine products of phenylalanine aminomutase catalysis
-
The substrate specificity of a Taxus-derived phenylalanine aminomutase (PAM) was investigated, and the enzyme was found to catalyze the conversion of variously substituted vinyl- and aryl-S-∞-alanines to corresponding β-amino acids. This study shows the b
- Klettke, Karin L.,Sanyal, Sanjit,Mutatu, Washington,Walker, Kevin D.
-
p. 6988 - 6989
(2008/02/06)
-
- Structure-activity relationships of 1,3,5-triazine-2,4,6-triones as human gonadotropin-releasing hormone receptor antagonists
-
SAR studies of 1,3,5-triazine-2,4,6-triones as human gonadotropin-releasing hormone receptor antagonists resulted in potent compounds. The best compound from the series had a binding affinity of 2 nM.
- Guo, Zhiqiang,Wu, Dongpei,Zhu, Yun-Fei,Tucci, Fabio C.,Regan, Collin F.,Rowbottom, Martin W.,Struthers, R. Scott,Xie, Qiu,Reijmers, Shelby,Sullivan, Susan K.,Sai, Yang,Chen, Chen
-
p. 3685 - 3690
(2007/10/03)
-
- A one-pot synthesis of 3-amino-3-arylpropionic acids
-
3-Aminopropionic acids (β-amino acids) are biologically active compounds of interest in medicinal and pharmaceutical chemistry. Twenty-one 3-amino-3-arylpropionic acids were synthesized via a facile one-pot synthesis. In addition, a series of mechanistic studies have been performed to optimize the production of these β-amino acids. The reaction mechanism of this one-pot synthesis of β-amino acids, as well as the electronic effect of para-substitution and the influence of solvent polarity on the proposed reaction mechanism are discussed.
- Tan,Weaver
-
p. 7449 - 7461
(2007/10/03)
-
- Effective cerebral antihypoxic activity of new aminocyclopentanones
-
Effective antihypoxic activity of new aminocyclopentanones which was higher than that of the reference compounds has been demonstrated by the SCR hypoxia test.
- Quermonne,Dallemagne,Louchahi-Raoul,Pilo,Rault,Robba
-
p. 961 - 965
(2007/10/02)
-
- Une synthese simple des premieres amino-3 indanones-1
-
The synthesis of various substituted 3-amino-1-indanones was achieved in five steps starting from corresponding benzaldehydes.
- Rault, Sylvain,Dallemagne, Patrick,Robba, Max
-
p. 1079 - 1083
(2007/10/02)
-