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Lee TH, Ham SL, Lee DY, Lee JR, Kim J, Kim CS. Structure Revision of Balsamisides A-D and Establishment of an Empirical Rule for Distinguishing Four Classes of Biflavonoids. JOURNAL OF NATURAL PRODUCTS 2022; 85:2461-2467. [PMID: 36222268 DOI: 10.1021/acs.jnatprod.2c00694] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Balsamisides A-D (1-4) are anti-inflammatory and neurotrophic biflavonoidal glycosides originally proposed to possess an epoxide functionality at the C-2/C-3 position. However, there are inconsistencies in their 13C NMR chemical shift values with those of previously reported analogs, indicating that reanalysis of NMR data for structures of 1-4 is necessary. Computational methods aided by the DP4+ probability technique and ECD calculations enabled structural reassignment of 1-4 to have a 2,3-dihydro-3-hydroxyfuran (3-DHF) instead of an epoxide. Additionally, two new biflavonoidal glycosides, balsamisides E and F (14 and 18), possessing a 2,3-dihydro-2-hydroxyfuran (2-DHF) and a 1,4-dioxane ring, respectively, were characterized by conventional NMR and MS data analysis as well as DP4+ and ECD methods. Systematic 13C NMR analysis was performed on the four aforementioned classes of biflavonoids with a 2- or 3-DHF, epoxide, or 1,4-dioxane. As a result, diagnostic 13C NMR chemical shift values of C-2/C-3 for rapid determination of these four biflavonoid classes were formulated, and based on this first empirical rule for (bi)flavonoids eight previously reported ones were structurally revised.
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Affiliation(s)
- Tae Hyun Lee
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Song Lim Ham
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Da Yeong Lee
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Ju Ryeong Lee
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Jonghwan Kim
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon16419, Republic of Korea
| | - Chung Sub Kim
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon16419, Republic of Korea
- School of Pharmacy, Sungkyunkwan University, Suwon16419, Republic of Korea
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2
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Maeno Y, Terada R, Kotaki Y, Cho Y, Konoki K, Yotsu-Yamashita M. Possible Biosynthetic Products and Metabolites of Kainic Acid from the Red Alga Digenea simplex and Their Biological Activity. JOURNAL OF NATURAL PRODUCTS 2019; 82:1627-1633. [PMID: 31117523 DOI: 10.1021/acs.jnatprod.9b00128] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Four kainic acid (KA, 1)-related compounds, 4-hydroxykainic acid (2), allo-4-hydroxykainic acid (3), N-dimethylallyl-l-glutamic acid (4), and N-dimethylallyl- threo-3-hydroxyglutamic acid (5), were isolated from the red alga Digenea simplex. The structures of these compounds were elucidated using spectroscopic methods. Compounds 2 and 3 are possible oxidative metabolites of KA and allo-KA (6), respectively. Compound 4 was recently reported as the biosynthetic precursor of KA, but the absolute configuration of 4 has not been previously determined. Herein, we determined the absolute configuration of 4 as 2( S) using advanced Marfey's method. Compound 5 is similar to N-geranyl-3( R)-hydroxy-l-glutamic acid (8), which was previously identified in a domoic acid (DA)-containing red alga. Compounds 5 and 8 are predicted to be biosynthetic byproducts of the radical-mediated cyclization reaction to form the pyrrolidine rings of KA and DA, respectively. Furthermore, the toxicities of 1-5 in mice were examined by intracerebroventricular injection. The toxicity of 2 was less than that of KA; however, the mice injected with 2 showed symptoms similar to those induced by KA, while 3-5 did not induce typical symptoms of KA in mice.
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Affiliation(s)
- Yukari Maeno
- Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8275 , Japan
| | - Ryuta Terada
- United Graduate School of Agricultural Sciences , Kagoshima University , 1-21-24 Korimoto , Kagoshima 890-0065 , Japan
| | - Yuichi Kotaki
- Fukushima College , 1-1 Chigoike Miyashiro , Fukushima 960-0181 , Japan
| | - Yuko Cho
- Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8275 , Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8275 , Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8275 , Japan
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3
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Affiliation(s)
- Mathew L. Piotrowski
- Department of Chemistry; The University of; London, Ontario Western Ontario Canada N6A 5B7
| | - Michael A. Kerr
- Department of Chemistry; The University of; London, Ontario Western Ontario Canada N6A 5B7
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4
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Nakatsuji H, Morimoto M, Misaki T, Tanabe Y. Mild, powerful, and robust methods for esterification, amide formation, and thioesterification between acid chlorides and alcohols, amines, thiols, respectively. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.08.117] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Hodgson DM, Hachisu S, Andrews MD. Stereocontrolled syntheses of kainoid amino acids from 7-azabicyclo[2.2.1]heptadienes using tandem radical addition-homoallylic radical rearrangement. J Org Chem 2006; 70:8866-76. [PMID: 16238320 DOI: 10.1021/jo0513865] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction; see text] N-Boc syn-7-(2-hydroxyethyl)-4-(alkyl or aryl)sulfonyl-2-azabicyclo[2.2.1]hept-5-enes serve as precursors in syntheses of the neuroexcitants 3-(carboxymethyl)pyrrolidine-2,4-dicarboxylic acid 43, alpha-kainic acid 12, alpha-isokainic acid 14, and alpha-dihydroallokainic acid 77. The key step in these syntheses is the intermolecular radical addition of 2-iodoethanol to a N-Boc 2-(alkyl or aryl)sulfonyl-7-azabicyclo[2.2.1]heptadiene 7 to induce nitrogen-directed homoallylic radical rearrangement. Oxidative cleavage of the resulting 2-azabicyclo[2.2.1]hept-5-enes provide straightforward access to polysubstituted pyrrolidines and, in particular, an efficient entry to the kainoid amino acids.
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Affiliation(s)
- David M Hodgson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, UK.
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6
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Ahern DG, Seguin RJ, Filer CN. Synthesis and characterization of [vinylidene-3H] (?)-?-kainic acid at high specific activity. J Labelled Comp Radiopharm 2002. [DOI: 10.1002/jlcr.562] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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7
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Baldwin JE, Fryer AM, Pritchard GJ. Parallel synthesis of novel heteroaromatic acromelic acid analogues from kainic acid. J Org Chem 2001; 66:2588-96. [PMID: 11304175 DOI: 10.1021/jo000846l] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A range of new C-4 heteroaromatic acromelic acid analogues has been synthesized in a parallel fashion from (-)-alpha-kainic acid 1. Protection of the amine and carboxylate groups of 1 followed by ozonolysis gave methyl ketone 8. A silyl enol ether 9, generated regiospecifically from the methyl ketone 8 using "kinetic" conditions, was brominated in situ with phenyltrimethylammonium perbromide to give the key alpha-bromo ketone 10. Parallel cyclization reactions of bromo ketone 10 with thioamides and thioureas were then performed. The aromatic heterocyclic derivatives 11a-d and 19 produced were deprotected to give the new kainoid amino acids 6a-d and 25 in excellent yield. Compounds 6a and 6c show strong binding to the kainate receptor. Reaction of 10 with alternative condensing agents was also briefly investigated.
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Affiliation(s)
- J E Baldwin
- The Dyson Perrins Laboratory, South Parks Road, Oxford OX1 3QY, U.K.
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8
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Baldwin JE, Fryer AM, Pritchard GJ. 1H NMR study of protected and unprotected kainoid amino acids: facile assignment of C-4 stereochemistry. J Org Chem 2001; 66:2597-601. [PMID: 11304176 DOI: 10.1021/jo000847d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The kainoid amino acids exhibit potent neuroexcitatory activity in the mammalian central nervous system. Around their pyrrolidine ring, a trans disposition between the C-2 and C-3 substituents and a cis relationship between the C-3 and C-4 substituents are crucial for their potent biological activity. During synthetic studies into the kainoids, we have established a straightforward, empirical rule, which allows the facile assignment of C-4 stereochemistry to both protected and unprotected kainoids. When pairs of C-4 epimers are available, the rule indicates that, when their (1)H NMR spectra are compared, one of the methylene protons on the C-3 side chain appears at significantly lower chemical shift in the C-3, C-4 cis isomer than the corresponding signal for the proton in the spectrum for the C-3, C-4 trans isomer. In addition, the rule states that the difference in chemical shift between the two individual protons on the C-3 side chain of the C-3, C-4 cis isomer is significantly greater than the corresponding difference for the C-3, C-4 trans isomer. The rule is demonstrated for kainoids possessing an unsaturated substituent at C-4 and when comparing spectra in D(2)O for pairs of unprotected C-4 epimers, the spectra were recorded at approximately the same pD.
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Affiliation(s)
- J E Baldwin
- The Dyson Perrins Laboratory, South Parks Road, Oxford OX1 3QY, U.K.
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9
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Xia Q, Ganem B. Asymmetric total synthesis of (-)-alpha-kainic acid using an enantioselective, metal-promoted ene cyclization. Org Lett 2001; 3:485-7. [PMID: 11434316 DOI: 10.1021/ol007009q] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[figure: see text] A short and efficient asymmetric total synthesis of the title compound 1, which is an important neurotransmitter, has been achieved. The synthesis features a metal-promoted, enantioselective ene reaction that provides entry into the kainic acid ring system from very simple precursors. Moreover, the zirconium-mediated Strecker reaction, which represents an outgrowth of earlier amide-to-imine methodology developed in our laboratory, demonstrates remarkable chemoselectivity and stereoselectivity.
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Affiliation(s)
- Q Xia
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
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10
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McDonald CE, Galka AM, Green AI, Keane JM, Kowalchick JE, Micklitsch CM, Wisnoski DD. Cyclization of unsaturated amides with triflic anhydride and samarium diiodide. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(00)01919-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Collado I, Ezquerra J, Mateo AI, Pedregal C, Rubio A. Stereocontrolled Synthesis of 5α- and 5β-Substituted Kainic Acids. J Org Chem 1999. [DOI: 10.1021/jo982109j] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Iván Collado
- Centro de Investigación Lilly, S. A. Avda de la Industria, 30. 28108 Alcobendas, Madrid, Spain
| | - Jesús Ezquerra
- Centro de Investigación Lilly, S. A. Avda de la Industria, 30. 28108 Alcobendas, Madrid, Spain
| | - Ana I. Mateo
- Centro de Investigación Lilly, S. A. Avda de la Industria, 30. 28108 Alcobendas, Madrid, Spain
| | - Concepción Pedregal
- Centro de Investigación Lilly, S. A. Avda de la Industria, 30. 28108 Alcobendas, Madrid, Spain
| | - Almudena Rubio
- Centro de Investigación Lilly, S. A. Avda de la Industria, 30. 28108 Alcobendas, Madrid, Spain
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12
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13
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14
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Diastereocontrolled synthesis of pyrrolidines by nickel promoted tandem cyclization-quenching of aminobromodienes. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(97)10220-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Todeschi N, Gharbi-Benarous J, Girault JP. Structure of kainic acid totally elucidated by NMR and molecular modelling. Bioorg Med Chem 1997; 5:1943-57. [PMID: 9370039 DOI: 10.1016/s0968-0896(97)00132-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
One class of glutamate receptors is characterized by the binding of the neuroexcitant and toxin kainic acid (KA), which contains an embedded L-glutamate moiety in a partially restricted (about the 2,3-bond) conformation. While there are a number of compounds that exhibit high specificity and selectivity at the ionotropic N-methyl-D-aspartate receptor, there has been a lack of selective and high-affinity ligands for the ionotropic KA subclass of excitatory amino acid receptors. This substance has received some attention recently being the least understood of the ionotropic type of glutamate receptor. The spatial orientation of the perceived functional groups of KA has been elucidated by a conformational analysis of an aqueous solution of KA using a combination of nuclear magnetic resonance (NMR) experimental results, mechanics and dynamics calculations, and theoretical simulation of NMR spectra. The weak pH-dependent effects on overall conformation and the structure of the principal '4E-envelope' KA conformer are established in aqueous solution. This study clearly shows the structural 'down' position of the double bond and the preferred 'g(-)-c' conformation of the C(3) carboxymethyl side-chain. The complex structure of this compound is thus definitively resolved. The conformation of the envelope ring such as C(3) carboxymethyl and C(4)-isopropenyl groups may strongly influence the potencies of KA interactions with the KA receptor.
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Affiliation(s)
- N Todeschi
- Université René Descartes-Paris V, Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (URA 400 CNRS), France
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16
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Baldwin JE, Bamford SJ, Fryer AM, Rudolph MP, Wood ME. Towards a versatile synthesis of kainoids II: Two methods for establishment of C-4 stereochemistry. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00191-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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