- Catalytic Asymmetric Synthesis of Unprotected β2-Amino Acids
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We report here a scalable, catalytic one-pot approach to enantiopure and unmodified β2-amino acids. A newly developed confined imidodiphosphorimidate (IDPi) catalyzes a broadly applicable reaction of diverse bis-silyl ketene acetals with a silylated aminomethyl ether, followed by hydrolytic workup, to give free β2-amino acids in high yields, purity, and enantioselectivity. Importantly, both aromatic and aliphatic β2-amino acids can be obtained using this method. Mechanistic studies are consistent with the aminomethylation to proceed via silylium-based asymmetric counteranion-directed catalysis (Si-ACDC) and a transition state to explain the enantioselectivity is suggested on the basis of density functional theory calculation.
- Zhu, Chendan,Mandrelli, Francesca,Zhou, Hui,Maji, Rajat,List, Benjamin
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supporting information
p. 3312 - 3317
(2021/04/07)
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- Absolute Configuration and Antibiotic Activity of Piceamycin
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The cultivation of a Streptomyces sp. SD53 strain isolated from the gut of the silkworm Bombyx mori produced two macrolactam natural products, piceamycin (1) and bombyxamycin C (2). The planar structures of 1 and 2 were identified by a combination of NMR, MS, and UV spectroscopic analyses. The absolute configurations were assigned based on chemical and chromatographic methods as well as ECD calculations. A new chromatography-based experimental method for determining the configurations of stereogenic centers β to nitrogen atoms in macrolactams was established and successfully applied in this report. These compounds exhibited significant bioactivities against the silkworm entomopathogen Bacillus thuringiensis and various human pathogens as well as human cancer cell lines. In particular, piceamycin potently inhibited Salmonella enterica and Proteus hauseri with MIC values of 0.083 μg/mL and 0.025 μg/mL, respectively. The biosynthetic pathway involved in the formation of the cyclopentenone moiety in piceamycin is discussed.
- Beom, Ji Yoon,Byun, Woong Sub,Chung, Beomkoo,Hong, Suckchang,Jeon, Chang-Wook,Kang, Saeyeon,Kwak, Youn-Sig,Lee, Jeeyeon,Lee, Sang Kook,Oh, Dong-Chan,Oh, Ki-Bong,Shin, Jongheon,Shin, Yern-Hyerk,Yoon, Yeo Joon
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- β2-Homo-amino acid scan of μ-selective opioid tetrapeptide TAPP
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TAPP (H-Tyr-d-Ala-Phe-Phe-NH2) is a potent, μ-selective opioid ligand. In order to gain further insights into pharmacophoric features of this tetrapeptide, we have performed a β2-Homo-amino acid (β2hAA) scan of the TAPP sequence. To this aim, 10 novel analogues have been synthesized and evaluated for μ-opioid and δ-opioid receptor affinity as well as for stability in human plasma. The derivatives included compounds in which a (R)- or (S)-β2-Homo-Homologue replaced the amino acids in the TAPP sequence. The derivatives with (R)- or (S)-β2hPhe4 turned out to bind μOR with affinities equal to that of the parent. β2hAAs in position 1 and 3 resulted in rather large affinity decreases, but the change differed depending on the stereochemistry. β2-Homologation in the second position gave derivatives with very poor μOR binding. According to molecular modelling, the presented α/β-peptides adopt a variety of binding poses with their common element being an ionic interaction between a protonable amine of the first residue and Asp147. A feature required for high μOR affinity seems the ability to accommodate the ring in the fourth residue in a manner similar to that found for TAPP. Contrary to what might be expected, several compounds were significantly less stable in human plasma than the parent compound.
- Kosson, Piotr,Lipiński, Piotr F. J.,Misicka, Aleksandra,Tymecka, Dagmara
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- Bombyxamycins A and B, Cytotoxic Macrocyclic Lactams from an Intestinal Bacterium of the Silkworm Bombyx mori
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Bombyxamycins A and B (1 and 2) were discovered from a silkworm gut Streptomyces bacterium. Spectroscopic analysis and multiple-step chemical derivatization identified them as 26-membered cyclic lactams with polyene features. Bombyxamycin A showed significant antibacterial and antiproliferative effects. The bombyxamycin biosynthetic gene cluster was identified by genetic analysis. Gene deletion experiments confirmed that the cytochrome P450 BomK is responsible for the generation of 2, which unprecedentedly bears tetrahydrofuran in its macrocyclic ring.
- Shin, Yern-Hyerk,Beom, Ji Yoon,Chung, Beomkoo,Shin, Yoonho,Byun, Woong Sub,Moon, Kyuho,Bae, Munhyung,Lee, Sang Kook,Oh, Ki-Bong,Shin, Jongheon,Yoon, Yeo Joon,Oh, Dong-Chan
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supporting information
p. 1804 - 1808
(2019/03/11)
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- Diastereoselective total synthesis and structural confirmation of surugamide F
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Surugamide F is a linear decapeptide (1) isolated along with the cyclic octapeptides surugamides A–E (2–6), from a marine-derived Streptomyces species. The linear peptide 1 is produced by two nonribosomal peptide synthetases (NRPSs) encoded in adjacent open reading frames, which are further flanked by an additional pair of NRPS genes responsible for the biosyntheses of the cyclic peptides 2–6. While the cyclic peptides 2–6 were identified to be cathepsin B inhibitors, the biological activity of the new metabolite 1 still remained unclear. In order to elucidate its unique biosynthetic pathway and biological activity in detail, we planned to develop an efficient synthetic route toward 1. Here we report the diastereoselective total synthesis of 1, utilizing 9-fluorenylmethyloxycarbonyl (Fmoc)-based solid-phase peptide synthesis. During this study, we found that the structural correction of 1 was required, due to the mislabeling of the commercially obtained 3-amino-2-methylpropionic acid, and the true structure of 1 was corroborated by the chemical synthesis and chromatographic comparison.
- Kuranaga, Takefumi,Fukuba, Atsuki,Ninomiya, Akihiro,Takada, Kentaro,Matsunaga, Shigeki,Wakimoto, Toshiyuki
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p. 637 - 641
(2018/06/11)
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- Modular Enzymatic Cascade Synthesis of Vitamin B5 and Its Derivatives
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Access to vitamin B5 [(R)-pantothenic acid] and both diastereoisomers of α-methyl-substituted vitamin B5 [(R)- and (S)-3-((R)-2,4-dihydroxy-3,3-dimethylbutanamido)-2-methylpropanoic acid] was achieved using a modular three-step biocatalytic cascade involving 3-methylaspartate ammonia lyase (MAL), aspartate-α-decarboxylase (ADC), β-methylaspartate-α-decarboxylase (CrpG) or glutamate decarboxylase (GAD), and pantothenate synthetase (PS) enzymes. Starting from simple non-chiral dicarboxylic acids (either fumaric acid or mesaconic acid), vitamin B5 and both diastereoisomers of α-methyl-substituted vitamin B5, which are valuable precursors for promising antimicrobials against Plasmodium falciparum and multidrug-resistant Staphylococcus aureus, can be generated in good yields (up to 70 %) and excellent enantiopurity (>99 % ee). This newly developed cascade process may be tailored and used for the biocatalytic production of various vitamin B5 derivatives by modifying the pantoyl or β-alanine moiety.
- Abidin, Mohammad Z.,Saravanan, Thangavelu,Zhang, Jielin,Tepper, Pieter G.,Strauss, Erick,Poelarends, Gerrit J.
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supporting information
p. 17434 - 17438
(2018/11/10)
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- Tripartilactam, a cyclobutane-bearing tricyclic lactam from a Streptomyces sp. in a dung beetle's brood ball
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Tripartilactam, a structurally unprecedented cyclobutane-bearing tricyclic lactam metabolite, was discovered from Streptomyces sp. isolated from a brood ball of the dung beetle, Copris tripartitus. The structure of this compound was elucidated by the combination of NMR, MS, UV, and IR spectroscopy and multistep chemical derivatization. Tripartilactam was evaluated as a Na+/K + ATPase inhibitor (IC50 = 16.6 μg/mL).
- Park, Seon-Hui,Moon, Kyuho,Bang, Hea-Son,Kim, Seong-Hwan,Kim, Dong-Gyu,Oh, Ki-Bong,Shin, Jongheon,Oh, Dong-Chan
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supporting information; experimental part
p. 1258 - 1261
(2012/05/04)
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- Asymmetric synthesis of β2-amino acids: 2-substituted-3-aminopropanoic acids from N-acryloyl SuperQuat derivatives
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Conjugate addition of lithium dibenzylamide to (S)-N(3)-acryloyl-4- isopropyl-5,5-dimethyloxazolidin-2-one (derived from l-valine) and alkylation of the resultant lithium β-amino enolate provides, after deprotection, a range of (S)-2-alkyl-3-aminopropanoic acids in good yield and high ee. Alternatively, via a complementary pathway, conjugate addition of a range of secondary lithium amides to (S)-N(3)-(2′-alkylacryloyl)-4-isopropyl-5,5- dimethyloxazolidin-2-ones, diastereoselective protonation with 2-pyridone, and subsequent deprotection furnishes a range of (R)-2-alkyl- and (R)-2-aryl-3-aminopropanoic acids in good yield and high ee. Additionally, the boron-mediated aldol reaction of β-amino N-acyl oxazolidinones is a highly diastereoselective method for the synthesis of a range of β-amino- β′-hydroxy N-acyl oxazolidinones. The Royal Society of Chemistry.
- Beddow, James E.,Davies, Stephen G.,Ling, Kenneth B.,Roberts, Paul M.,Russell, Angela J.,Smith, Andrew D.,Thomson, James E.
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p. 2812 - 2825
(2008/03/12)
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- Enantioselective synthesis of β-amino acids Part 13. Diastereoselective alkylation of dianions derived from chiral analogs of β-aminopropanoic acid containing the α-phenylethyl group
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Inexpensive acryloyl chloride was converted in 91% overall yield to two derivatives of β-alanine, (R,R,R)-and (R,R,S)-6, containing two chiral auxiliaries. C-Alkylation of (R,R,R)- and (R,R,S)-6 via a dianion derivative, was performed by direct metallation with 2.2 equiv. of lithium hexamethyldisilazane (LHMDS) in THF at - 78°. C-Alkylation of (R,R,S)-6-Li2 ('matched' pair of chiral auxiliaries) afforded the mono-alkylated products 8-11 in 29-96% yield and 54-95% stereoselectivity. Employment of LiCl as an additive generally increased stereoselectivities, whereas the effect of HMPA as a cosolvent was erratic. Chemical correlation of the major diastereoisomer from the alkylation reactions with (S)-α-alkyl-β-alanine (12-15) showed that addition of the electrophile preferentially takes place on the enolate's Si-face. This conclusion is also supported by molecular-modeling studies (ab initio HF/3-21G), which indicate that the lowest-energy conformation for (R,R,S)-6-Li2 presents the more sterically hindered Re-face of the enolate. The theoretical studies also predict a determining role for N-Li-O chelation in (R,R,S)-6-Li2, giving rise to an interesting 'ion-triplet' configuration for the dilithium dianion.
- Gutierrez-Garcia, Victor Manuel,Reyes-Rangel, Gloria,Munoz-Muniz, Omar,Juaristi, Eusebio
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p. 4189 - 4199
(2007/10/03)
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- A new enantioselective synthesis of β-amino acids
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Enantioselective hydrogenation of some α,β-unsaturated nitriles and their corresponding methyl esters bearing a phthalimidomethyl substituent at the α-carbon using Rh-DuPHOS catalysts afforded β-amino acid precursors with modest e.e.s of up to 48%. Hydrogenation of the α,β-unsaturated methyl esters using a Ru-BINAP catalyst gave higher e.e.s of up to 84%. Method development for the determination of the enantiomeric excesses of these derivatives using chiral HPLC is also reported.
- Saylik, Dilek,Campi, Eva M.,Donohue, Andrew C.,Jackson,Robinson, Andrea J.
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p. 657 - 667
(2007/10/03)
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- Enantioselective synthesis of α,β-substituted β-amino acids
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Chiral derivative 3 was shown to be a precursor of α and β-substituted β-amino acids as well as α,β-disubstituted β-amino acids. The key steps of the procedure are a diastereoselective alkylation of synthon 3 by organocuprates reagents and a diastereoselective alkylation of the alkylated adduct.
- Agami, Claude,Cheramy, Sandrine,Dechoux, Luc,Melaimi, Mohand
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p. 195 - 200
(2007/10/03)
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- Synthesis of alpha-substituted beta-amino acids using pseudoephedrine as a chiral auxiliary.
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[reaction: see text] beta-Amino acids are becoming increasingly attractive as intermediates in the synthesis of a variety of molecular structures. However, few methods are available for the synthesis of alpha-substituted beta-amino acids that are both readily scalable and highly stereoselective. Herein we report a new method for synthesizing alpha-substituted beta-amino acids that satisfies both of these requirements using enantiomerically pure pseudoephedrine as a chiral auxiliary.
- Nagula,Huber,Lum,Goodman
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p. 3527 - 3529
(2007/10/03)
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- Stereoselective α-alkylation of new chiral auxiliaries: An access to enantiomerically pure α- and α,β-substituted β-amino acids
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New bicyclic heterocycles 5, which are potentially useful for the enantioselective synthesis of substituted β-amino acids, have been synthesized. A study on the α-alkylation of these chiral auxiliaries is presented. An optically pure β-amino acid was obtained in excellent yield from its masked chiral derivative 6a.
- Agami, Claude,Cheramy, Sandrine,Dechoux, Luc
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p. 1838 - 1840
(2007/10/03)
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- Palladium-catalysed asymmetric allylic substitution: Synthesis of α- and β-amino acids
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Methodology has been established for the formation of enantiomerically enriched α-amino acids using palladium-catalysed allylic amination. The formation of enantiomerically enriched allylamines has been achieved with high enantioselectivity. Oxidative cleavage of the allylamines provides arylglycine and glutamic acid derivatives. Additionally, enantiomerically enriched β-amino acids have been prepared in high enantiomeric excess. Palladium-catalysed asymmetric allylic substitution is used as the key synthetic transformation.
- Bower, Justin F.,Jumnah, Roshan,Williams, Andrew C.,Williams, Jonathan M. J.
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p. 1411 - 1420
(2007/10/03)
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- 3-Methylazetidin-2-one and its precursors: Optical resolution and absolute configurations
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Enantiomers of 3-methylazetidin-2-one - (3R)-(+)- and (3S)-(-)-1 and 3-amino-2-methylpropionic acid - (2R)-(-)- and (2S)-(+)-2 were obtained from corresponding diastereomers of methyl (αS)-N-α-methylbenzyl-3-amino-2-methylpropionate 3A,B which had been separated by recrystallization of their salts 4A,B with p-toluenesulfonic acid. The absolute configurations of azetidinones (+)- and (-)-1 and their diastereomeric precursors, i.e. amino esters 3A,B, (αS)-N-α-methylbenzyl-3-amino-2-methylpropionic acids 5A,B, and (αS)-N-α-methylbenzyl-3-methylazetidin-2-ones 6A,B were established by conversion of (+)-1 to amino acid (2R)-(-)-2 and of amino acid (2S)-(+)-2 to (-)-1.
- Shustov,Rauk
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p. 699 - 708
(2007/10/03)
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- Enantioselective synthesis of β-amino acids. 7. Preparation of enantiopure α-substituted β-amino acids from 1-benzoyl-2(S)-tert-butyl-3-methylperhydropyrimidin-4-one
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Inexpensive natural α-amino acid L-asparagine was efficiently converted to either (R)- or (S)-α-alkylated β-amino acids in enantiomerically pure state. The key intermediate in this protocol is the enantiopure N,N-acetal pyrimidinone (S)-1, a masked chiral derivative of β-alanine.
- Juaristi, Eusebio,Quintana, Delia,Balderas, Margarita,Garcia-Perez, Enrique
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p. 2233 - 2246
(2007/10/03)
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- Stereochemistry of Catabolism of the DNA Base Thymine and of the Anticancer Drug 5-Fluorouracil
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(2S)-3-Amino-2-methylpropanoic acid (6) and (2RS,3S)--3-amino-2-methylpropanoic acid (14) have been synthesized and used to provide an assay which shows that the catabolism of the DNA base thymine (1; R = Me) proceeds by overall anti addition of hydrogen to the pyrimidine at the si face at C-5 and the si face at C-6.X-Ray structure analysis of a derivative of the product of reaction of N,N-dibenzyl-L-serine methyl ester (15; R = Me) with (diethylamino)sulphur trifluoride followed by deprotection has shown it to be (2R)-3-amino-2-fluoropropanoic acid (19; R = H).This was identical with the product of catabolism of the anti-cancer drug 5-fluorouracil (1; R = F).Esters of (2R,3S)-- and (2R,3R)--3-amino-2-fluoropropanoic acids have been synthesized and used to provide an assay which shows that catabolism of the anti-cancer drug 5-fluorouracil (1; R = F) proceeds with the same absolute stereochemistry as is found in catabolism of thymine (1; R = Me).
- Gani, David,Hitchcock, Peter B.,Young, Douglas W.
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p. 1363 - 1372
(2007/10/02)
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- Stereochemistry of the Metabolism of the DNA Base Thymine and the Drug 5-Fluorouracil
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The enzyme dihydrothymine dehydrogenase reduces both the DNA base thymine and the anti-cancer drug 5-fluorouracil by overall trans addition of hydrogen, at the si-face at C-5 and the si-face at C-6.
- Gani, David,Hitchcock, Peter B.,Young, Douglas W.
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p. 898 - 900
(2007/10/02)
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