1
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Luo Z, Xu L, Tang X, Zhao X, He T, Lubell WD, Zhang J. Synthesis and biological evaluation of novel all-hydrocarbon cross-linked aza-stapled peptides. Org Biomol Chem 2022; 20:7963-7971. [PMID: 36190455 DOI: 10.1039/d2ob01496c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Novel all-hydrocarbon cross-linked aza-stapled peptides were designed and synthesized for the first time by ring-closing metathesis between two aza-alkenylglycine residues. Three aza-stapled peptidic analogues based on the peptide dual inhibitor of p53-MDM2/MDMX interactions were synthesized and screened for biological activities. Among the three aza-stapled peptides, aSPDI-411 displayed increased anti-tumor activity, binding affinities to both MDM2 and MDMX, and cell membrane permeability compared to its linear peptide counterpart.
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Affiliation(s)
- Zhihong Luo
- Innovative Drug Research Centre (IDRC), Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P. R. China.
| | - Lei Xu
- Innovative Drug Research Centre (IDRC), Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P. R. China.
| | - Xiaomin Tang
- Innovative Drug Research Centre (IDRC), Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P. R. China.
| | - Xuejun Zhao
- Innovative Drug Research Centre (IDRC), Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P. R. China.
| | - Tong He
- Innovative Drug Research Centre (IDRC), Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P. R. China.
| | - William D Lubell
- Département de Chimie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada.
| | - Jinqiang Zhang
- Innovative Drug Research Centre (IDRC), Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P. R. China. .,Chongqing University Industrial Technology Research Institute, Chongqing 401329, People's Republic of China
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2
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Otani T, Hattori Y, Akaji K, Kobayashi K. Macrocyclic BACE1 inhibitors with hydrophobic cross-linked structures: Optimization of ring size and ring structure. Bioorg Med Chem 2021; 52:116517. [PMID: 34800875 DOI: 10.1016/j.bmc.2021.116517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 11/29/2022]
Abstract
Based on the X-ray crystallography of recombinant BACE1 and a hydroxyethylamine-type peptidic inhibitor, we introduced a cross-linked structure between the P1 and P3 side chains of the inhibitor to enhance its inhibitory activity. The P1 and P3 fragments bearing terminal alkenes were synthesized, and a ring-closing metathesis of these alkenes was used to construct the cross-linked structure. Evaluation of ring size using P1 and P3 fragments with various side chain lengths revealed that 13-membered rings were optimal, although their activity was reduced compared to that of the parent compound. Furthermore, the optimal ring structure was found to be a macrocycle with a dimethyl branched substituent at the P3 β-position, which was approximately 100-fold more active than the non-substituted macrocycle. In addition, the introduction of a 4-carboxymethylphenyl group at the P1' position further improved the activity.
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Affiliation(s)
- Takuya Otani
- Department of Medicinal Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Yasunao Hattori
- Center for Instrumental Analysis, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Kenichi Akaji
- Department of Medicinal Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Kazuya Kobayashi
- Department of Medicinal Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan.
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3
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Jiang CS, Zhou ZF, Yang XH, Lan LF, Gu YC, Ye BP, Guo YW. Antibacterial sorbicillin and diketopiperazines from the endogenous fungus Penicillium sp. GD6 associated Chinese mangrove Bruguiera gymnorrhiza. Chin J Nat Med 2018; 16:358-365. [PMID: 29860997 DOI: 10.1016/s1875-5364(18)30068-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Indexed: 02/06/2023]
Abstract
One new sorbicillin derivative, 2-deoxy-sohirnone C (1), one new diketopiperazine alkaloid, 5S-hydroxynorvaline-S-Ile (2), and two naturally occurring diketopiperazines, 3S-hydroxylcyclo(S-Pro-S-Phe) (3) and cyclo(S-Phe-S-Gln) (4), together with three known compounds were isolated from the Chinese mangrove endophytic fungus Penicillium sp. GD6. Their structures were determined on the basis of extensive spectroscopic analyses and by comparison with literature data. The absolute configuration of 3-hydroxyl moiety in 3 was determined by Mosher's method, while the absolute stereochemistry of 2 and 4 was established by comparison with the CD spectra of natural and synthesized diketopiperazines. Compound 1 showed moderate antibacterial activity against Methicillin-resistant Staphylococcus aureus with a MIC value of 80 μg·mL-1.
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Affiliation(s)
- Cheng-Shi Jiang
- China State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; School of Biological Science and Technology, University of Jinan, Jinan 250022, China
| | - Zhen-Fang Zhou
- China State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiao-Hong Yang
- School of Life Science & Technology, China Pharmaceutical University, Nanjing 210009, China
| | - Le-Fu Lan
- China State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yu-Cheng Gu
- Syngenta Jealott's Hill International Research Centre, Berkshire RG42 6EY, United Kingdom
| | - Bo-Ping Ye
- School of Life Science & Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Yue-Wei Guo
- China State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
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4
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Koszelewski D, Trzepizur D, Zaorska E, Madej A, Brodzka A, Paprocki D, Borys F, Wilk M, Ostaszewski R. Facile Conversion of α-Acyloxy Amides into 3-Hydroxy-lactams. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800605] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Dominik Koszelewski
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Damian Trzepizur
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Ewelina Zaorska
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Arleta Madej
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Anna Brodzka
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Daniel Paprocki
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Filip Borys
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Monika Wilk
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
| | - Ryszard Ostaszewski
- Institute of Organic Chemistry; Polish Academy of Sciences; Kasprzaka 44/52 01-224 Warsaw Poland
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5
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Zhang J, Wang S, Bai Y, Guo Q, Zhou J, Lei X. Total Syntheses of Natural Metallophores Staphylopine and Aspergillomarasmine A. J Org Chem 2017; 82:13643-13648. [DOI: 10.1021/acs.joc.7b02342] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Jian Zhang
- School
of Life Sciences, Peking University, Beijing 100871, China
| | - Sanshan Wang
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic
Chemistry and Molecular Engineering of Ministry of Education, Department
of Chemical Biology, College of Chemistry and Molecular Engineering,
Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center
for Life Sciences, Peking University, Beijing 100871, China
| | - Yingjie Bai
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic
Chemistry and Molecular Engineering of Ministry of Education, Department
of Chemical Biology, College of Chemistry and Molecular Engineering,
Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center
for Life Sciences, Peking University, Beijing 100871, China
| | - Qianqian Guo
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic
Chemistry and Molecular Engineering of Ministry of Education, Department
of Chemical Biology, College of Chemistry and Molecular Engineering,
Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center
for Life Sciences, Peking University, Beijing 100871, China
| | - Jiang Zhou
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic
Chemistry and Molecular Engineering of Ministry of Education, Department
of Chemical Biology, College of Chemistry and Molecular Engineering,
Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center
for Life Sciences, Peking University, Beijing 100871, China
| | - Xiaoguang Lei
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic
Chemistry and Molecular Engineering of Ministry of Education, Department
of Chemical Biology, College of Chemistry and Molecular Engineering,
Synthetic and Functional Biomolecules Center and Peking-Tsinghua Center
for Life Sciences, Peking University, Beijing 100871, China
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6
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Jones BD, Tochowicz A, Tang Y, Cameron MD, McCall LI, Hirata K, Siqueira-Neto JL, Reed SL, McKerrow JH, Roush WR. Synthesis and Evaluation of Oxyguanidine Analogues of the Cysteine Protease Inhibitor WRR-483 against Cruzain. ACS Med Chem Lett 2016; 7:77-82. [PMID: 26819670 DOI: 10.1021/acsmedchemlett.5b00336] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 12/07/2015] [Indexed: 11/29/2022] Open
Abstract
A series of oxyguanidine analogues of the cysteine protease inhibitor WRR-483 were synthesized and evaluated against cruzain, the major cysteine protease of the protozoan parasite Trypanosoma cruzi. Kinetic analyses of these analogues indicated that they have comparable potency to previously prepared vinyl sulfone cruzain inhibitors. Co-crystal structures of the oxyguanidine analogues WRR-666 (4) and WRR-669 (7) bound to cruzain demonstrated different binding interactions with the cysteine protease, depending on the aryl moiety of the P1' inhibitor subunit. Specifically, these data demonstrate that WRR-669 is bound noncovalently in the crystal structure. This represents a rare example of noncovalent inhibition of a cysteine protease by a vinyl sulfone inhibitor.
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Affiliation(s)
- Brian D. Jones
- Department
of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Anna Tochowicz
- Department
of Pathology and Sandler Center for Drug Discovery, University of California-San Francisco, 1700 Fourth Street, San
Francisco, California 94158-2250, United States
| | - Yinyan Tang
- Small
Molecule Discovery Center, University of California-San Francisco, 1700 Fourth Street, San Francisco, California 94158-2250, United States
| | - Michael D. Cameron
- Department
of Molecular Therapeutics, The Scripps Research Institute, 130 Scripps
Way, Jupiter, Florida 33458, United States
| | - Laura-Isobel McCall
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Ken Hirata
- Department
of Pathology, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jair L. Siqueira-Neto
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Sharon L. Reed
- Departments
of Pathology and Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - James H. McKerrow
- Department
of Pathology and Sandler Center for Drug Discovery, University of California-San Francisco, 1700 Fourth Street, San
Francisco, California 94158-2250, United States
| | - William R. Roush
- Department
of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
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7
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Highly stable atropisomers by electrophilic amination of a chiral γ-lactam within the synthesis of an elusive conformationally restricted analogue of α-methylhomoserine. Amino Acids 2015; 48:461-78. [DOI: 10.1007/s00726-015-2100-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 09/11/2015] [Indexed: 02/01/2023]
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8
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Demmer CS, Møller C, Brown PMGE, Han L, Pickering DS, Nielsen B, Bowie D, Frydenvang K, Kastrup JS, Bunch L. Binding mode of an α-amino acid-linked quinoxaline-2,3-dione analogue at glutamate receptor subtype GluK1. ACS Chem Neurosci 2015; 6:845-54. [PMID: 25856736 DOI: 10.1021/acschemneuro.5b00038] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Two α-amino acid-functionalized quinoxalines, 1a (CNG-10301) and 1b (CNG-10300), of a quinoxaline moiety coupled to an amino acid moiety were designed, synthesized, and characterized pharmacologically. While 1a displayed low affinity at native AMPA, KA, and NMDA receptors, and at homomeric GluK1,3 receptors, the affinity for GluK2 was in the midmicromolar range (Ki = 136 μM), 1b displayed low to midmicromolar range binding affinity at all the iGluRs (Ki = 9-126 μM). In functional experiments (outside-out patches excised from transfected HEK293T cells), 100 μM 1a partially blocked GluK1 (33% peak response), while GluK2 was unaffected (96% peak response). Furthermore, 1a was shown not to be an agonist at GluK1 and GluK2 at 100 μM. On the other hand, 100 μM 1b fully antagonized GluK1 (8% peak response) but only partially blocked GluK2 (33% peak response). An X-ray structure at 2.3 Å resolution of 1b in the GluK1-LBD (ligand-binding domain) disclosed an unexpected binding mode compared to the predictions made during the design phase; the quinoxaline moiety remains to act as an amino acid bioisostere, but the amino acid moiety is oriented into a new area within the GluK1 receptor. The structure of the GluK1-LBD with 1b showed a large variation in domain openings of the three molecules from 25° to 49°, demonstrating that the GluK1-LBD is capable of undergoing major domain movements.
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9
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Synthesis of a cyclic isostere of α-methyl homoserine by a stereoselective acylation–alkylation sequence of a chiral γ-lactam. Amino Acids 2014; 46:1097-103. [DOI: 10.1007/s00726-014-1671-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 01/09/2014] [Indexed: 10/25/2022]
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10
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Ottersbach PA, Schmitz J, Schnakenburg G, Gütschow M. An access to aza-Freidinger lactams and E-locked analogs. Org Lett 2013; 15:448-51. [PMID: 23320486 DOI: 10.1021/ol3030583] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Freidinger lactams, possessing a peptide bond configuration locked to Z, are important key elements of conformationally restricted peptidomimetics. In the present work, the C(α)H(i+1) unit has been replaced by N, leading to novel aza-Freidinger lactams. A synthesis to corresponding building blocks and their E-locked analogs is introduced. The versatile buildings blocks reported here are expected to serve as useful elements in peptide synthesis.
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Affiliation(s)
- Philipp A Ottersbach
- Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
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11
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Ottersbach PA, Schnakenburg G, Gütschow M. Induction of chirality: experimental evidence of atropisomerism in azapeptides. Chem Commun (Camb) 2012; 48:5772-4. [PMID: 22552375 DOI: 10.1039/c2cc31161e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Methylation of the peptide bond in model azadipeptides leads to the E configuration and hence to atropisomerism due to a restricted rotation around the N-N axis.
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Affiliation(s)
- Philipp A Ottersbach
- Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
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12
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Szostak M, Spain M, Procter DJ. Selective synthesis of 3-hydroxy acids from Meldrum's acids using SmI2-H2O. Nat Protoc 2012; 7:970-7. [DOI: 10.1038/nprot.2012.034] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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14
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Affiliation(s)
- Bimal K. Banik
- Dept. Chemistry, University of Texas-Pan American, W. University Drive 1201, Edinburg, 78539 USA
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15
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Swamy KCK, Kumar NNB, Balaraman E, Kumar KVPP. Mitsunobu and Related Reactions: Advances and Applications. Chem Rev 2009; 109:2551-651. [PMID: 19382806 DOI: 10.1021/cr800278z] [Citation(s) in RCA: 873] [Impact Index Per Article: 58.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K. C. Kumara Swamy
- School of Chemistry, University of Hyderabad, Hyderabad − 500046, A. P., India
| | - N. N. Bhuvan Kumar
- School of Chemistry, University of Hyderabad, Hyderabad − 500046, A. P., India
| | - E. Balaraman
- School of Chemistry, University of Hyderabad, Hyderabad − 500046, A. P., India
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16
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Joce C, Caryl J, Stockley PG, Warriner S, Nelson A. Identification of stable S-adenosylmethionine (SAM) analogues derivatised with bioorthogonal tags: effect of ligands on the affinity of the E. coli methionine repressor, MetJ, for its operator DNA. Org Biomol Chem 2008; 7:635-8. [PMID: 19194573 PMCID: PMC2650099 DOI: 10.1039/b816495a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The efficient synthesis of a range of stable SAM mimetics, and their ability to promote the binding of the E. coli methionine repressor (MetJ) to its operator DNA, is described. Active analogues functionalised with bioorthogonal tags were identified.
The efficient synthesis of a range of stable SAM mimetics, and their ability to promote the binding of the E. coli methionine repressor (MetJ) to its operator DNA, is described.
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Affiliation(s)
- Catherine Joce
- School of Chemistry, University of Leeds, Leeds, UKLS2 9JT, UK
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17
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Kudaj A, Olma A. A convenient transformation of α-alkylserines into α-halogenomethyl-α-alkylglycines. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.08.098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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18
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Golantsov NE, Karchava AV, Yurovskaya MA. The Mitsunobu reaction in the chemistry of nitrogen-containing heterocyclic compounds. The formation of heterocyclic systems (review). Chem Heterocycl Compd (N Y) 2008. [DOI: 10.1007/s10593-008-0042-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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19
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Palomo C, Aizpurua JM, Balentova E, Jimenez A, Oyarbide J, Fratila RM, Miranda JI. Synthesis of β-Lactam Scaffolds for Ditopic Peptidomimetics. Org Lett 2006; 9:101-4. [PMID: 17192095 DOI: 10.1021/ol0626241] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Ring opening of alpha-substituted-alpha-methoxycarbonyl-N-nosylaziridines provides a practical access to enantiopure alpha,alpha'-disubstituted beta-lactam scaffolds, novel types of ditopic reverse turn surrogates. The procedure is general, short, and high yielding and starts from handy alpha-substituted serinates and alpha-amino acid derivatives.
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Affiliation(s)
- Claudio Palomo
- Departamento de Química OrgAnica-I, Universidad del País Vasco, Facultad de Química, Apdo 1072, 20080 San SebastiAn, Spain
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20
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Palomo C, Aizpurua JM, Benito A, Cuerdo L, Fratila RM, Miranda JI, Linden A. Functionalization of N-[(Silyl)methyl]-β-lactam Carbanions with Carbon Electrophiles. J Org Chem 2006; 71:6368-73. [PMID: 16901117 DOI: 10.1021/jo060537g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Latent acidity of alpha-alkyl-alpha-amino-N-[(silyl)methyl]-beta-lactams enabled a concise entry to lithium nonenolate N-methyl-azetidinone carbanions lithiated alpha' to the beta-lactam nitrogen, owing to the stabilizing "alpha-effect" of one or two trimethylsilyl groups. (n)BuLi/TMEDA and (t)BuLi/TMEDA were the bases of choice for complete deprotonation of di- and monosilylated beta-lactams, respectively. Trapping of the resulting carbanions with alkyl halides provided the corresponding N-[(alpha'-silyl)-alkyl]-beta-lactams, while carbon dioxide and related electrophiles such as benzyl chloroformates or isocyanates, afforded the corresponding silicon-free N-carboxymethyl-, N-benzyloxycarbonylmethyl-, and N-amidomethyl-beta-lactams in a single synthetic step. Likely structures of these unprecedented lithiated N-[(silyl)methyl]-beta-lactams were studied by MO calculations (B3LYP/6-31G**), and the origin of their relative stability was briefly discussed.
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Affiliation(s)
- Claudio Palomo
- Departamento de Química Organica-I, Facultad de Química, Universidad del País Vasco, Apdo 1072, 20080 San Sebastian, Spain.
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