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Riesco-Llach G, Planas M, Feliu L, Joule JA. 2(1 H)-Pyrazinones from acyclic building blocks: methods of synthesis and further derivatizations. RSC Adv 2023; 13:1162-1184. [PMID: 36686909 PMCID: PMC9811941 DOI: 10.1039/d2ra07227k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 12/23/2022] [Indexed: 01/06/2023] Open
Abstract
Pyrazinones (2(1H)-pyrazinones) are found as components of a range of natural substances and are involved in the preparation of a great number of bioactive molecules. Synthesis of such compounds, and analogues, requires knowledge of the heterocyclic properties of pyrazinones and, in particular, methods for their ring construction. This review deals with the strategies that have been developed for the synthesis of pyrazinones from acyclic precursors, especially α-amino acid-derived units, from the first examples in 1905 up to the most recent in 2021.
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Affiliation(s)
- Gerard Riesco-Llach
- LIPPSO, Department of Chemistry, Universitat de Girona Maria Aurèlia Capmany 69 Girona 17003 Spain
| | - Marta Planas
- LIPPSO, Department of Chemistry, Universitat de Girona Maria Aurèlia Capmany 69 Girona 17003 Spain
| | - Lidia Feliu
- LIPPSO, Department of Chemistry, Universitat de Girona Maria Aurèlia Capmany 69 Girona 17003 Spain
| | - John A Joule
- The School of Chemistry, The University of Manchester Manchester M13 9PL UK
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Zarezin DP, Nenajdenko VG. Diazocarbonyl derivatives of amino acids: unique chiral building blocks for the synthesis of biologically active compounds. RUSSIAN CHEMICAL REVIEWS 2019. [DOI: 10.1070/rcr4852] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This review deals with applications of chiral α-amino diazoketones, α-amino acid derivatives, in the synthesis of various biologically active compounds. General approaches to the synthesis of chiral α-amino diazoketones, including the Arndt – Eistert reaction, acylation of trimethylsilyldiazomethanes, etc., are discussed. Due to the presence of three functional groups, these building blocks can be used to produce a wide range of organic compounds with potential physiological activity, ranging from various heterocyclic compounds to peptidomimetics. Methods for the synthesis of β-amino acid-containing peptides and depsipeptides, amino acid derivatives and heterocyclic compounds with three- to seven-membered rings are considered.
The bibliography includes 226 references.
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Shiotani K, Li T, Miyazaki A, Tsuda Y, Bryant SD, Ambo A, Sasaki Y, Lazarus LH, Okada Y. Synthesis of 3,6-bis[H-Tyr/H-Dmt-NH(CH2)m,n]-2(1H)pyrazinone derivatives: function of alkyl chain length on opioid activity. Bioorg Med Chem Lett 2006; 16:5793-6. [PMID: 16949282 PMCID: PMC2636969 DOI: 10.1016/j.bmcl.2006.08.079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Revised: 07/22/2006] [Accepted: 08/17/2006] [Indexed: 10/24/2022]
Abstract
Dimeric opioid analogues linked to a pyrazinone platform, 3-[Tyr/Dmt-NH(CH2)m]-6-[Tyr/Dmt-NH(CH2)n]-2(1H)-pyrazinone (m, n=3 or 4), were synthesized. The Tyr-containing compound (m=4, n=3) exhibited mu-receptor affinity (K(i)mu; 7.58 nM) comparable to that of morphine, while the Dmt derivatives exhibited considerably higher affinity (K(i)mu; 0.021-0.051 nM) with corresponding agonism (IC50=1.79-4.93 nM). Interestingly one compound (m=4, n=3) revealed modest delta-opioid agonism; the converse analogue (m=3, n=4), however, was inactive in MVD assay.
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Affiliation(s)
- Kimitaka Shiotani
- The Graduate School of Food and Medicinal Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
| | - Tingyou Li
- The Graduate School of Food and Medicinal Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
| | - Anna Miyazaki
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
| | - Yuko Tsuda
- The Graduate School of Food and Medicinal Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
| | - Sharon D. Bryant
- The Graduate School of Food and Medicinal Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
| | - Akihiro Ambo
- Department of Biochemistry, Tohoku Pharmaceutical University, Aoba-ku, Sendai 981-8558, Japan
| | - Yusuke Sasaki
- Department of Biochemistry, Tohoku Pharmaceutical University, Aoba-ku, Sendai 981-8558, Japan
| | - Lawrence H. Lazarus
- Medicinal Chemistry Group, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 U.S.A
| | - Yoshio Okada
- The Graduate School of Food and Medicinal Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
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4
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Kaval N, Appukkuttan P, Van der Eycken E. The Chemistry of 2-(1H)-Pyrazinones in Solution and on Solid Support. TOPICS IN HETEROCYCLIC CHEMISTRY 2006. [DOI: 10.1007/7081_007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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A. Joule J, Helliwell M, You Y. The 1,3-Dipolar Cycloaddition of Methyl Acrylate to Hindered 3-Oxidopyraziniums. HETEROCYCLES 2006. [DOI: 10.3987/com-06-s(w)22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Li T, Fujita Y, Shiotani K, Miyazaki A, Tsuda Y, Ambo A, Sasaki Y, Jinsmaa Y, Marczak E, Bryant SD, Salvadori S, Lazarus LH, Okada Y. Potent Dmt-Tic Pharmacophoric δ- and μ-Opioid Receptor Antagonists. J Med Chem 2005; 48:8035-44. [PMID: 16335927 DOI: 10.1021/jm050377l] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of dimeric Dmt-Tic (2',6'-dimethyl-L-tyrosyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) analogues (8-14, 18-22) were covalently linked through diaminoalkane and symmetric or asymmetric 3,6-diaminoalkyl-2(1H)-pyrazinone moieties. All the compounds exhibited high affinity for both delta-opioid receptors [Ki(delta) = 0.06-1.53 nM] and mu-opioid receptors [Ki(mu) = 1.37-5.72 nM], resulting in moderate delta-receptor selectivity [Ki(mu)/Ki(delta) = 3-46]. Regardless of the type of linker between the Dmt-Tic pharmacophores, delta-opioid-mediated antagonism was extraordinarily high in all analogues (pA2 = 10.42-11.28), while in vitro agonism (MVD and GPI bioassays) was essentially absent (ca. 3 to >10 microM). While an unmodified N-terminus (9, 13, 18) revealed weak mu-opioid antagonism (pA2 = 6.78-6.99), N,N'-dimethylation (21, 22), which negatively impacts on mu-opioid-associated agonism (Balboni et al., Bioorg. Med. Chem. 2003, 11, 5435-5441), markedly enhanced mu-opioid antagonism (pA2 = 8.34 and 7.71 for 21 and 22, respectively) without affecting delta-opioid activity. These data are the first evidence that a single dimeric opioid ligand containing the Dmt-Tic pharmacophore exhibits highly potent delta- and mu-opioid antagonist activities.
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MESH Headings
- Animals
- Binding, Competitive
- Brain/metabolism
- Diamines/chemical synthesis
- Diamines/chemistry
- Diamines/pharmacology
- Dipeptides/chemical synthesis
- Dipeptides/chemistry
- Dipeptides/pharmacology
- Guinea Pigs
- Ileum/drug effects
- Ileum/physiology
- In Vitro Techniques
- Ligands
- Male
- Mice
- Muscle, Smooth/drug effects
- Muscle, Smooth/physiology
- Peptides/chemical synthesis
- Peptides/chemistry
- Peptides/pharmacology
- Pyrazines/chemical synthesis
- Pyrazines/chemistry
- Pyrazines/pharmacology
- Radioligand Assay
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Structure-Activity Relationship
- Tetrahydroisoquinolines/chemical synthesis
- Tetrahydroisoquinolines/chemistry
- Tetrahydroisoquinolines/pharmacology
- Vas Deferens/drug effects
- Vas Deferens/physiology
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Affiliation(s)
- Tingyou Li
- The Graduate School of Food and Medicinal Sciences and Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan
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Miyazaki A, Fujisawa Y, Shiotani K, Fujita Y, Li T, Tsuda Y, Yokoi T, Bryant SD, Lazarus LH, Okada Y. Studies on the mechanism of 1,2-dihydropyrazin-2-one ring formation from dipeptidyl chloromethyl ketone and its chemical properties: immediate deamination during catalytic hydrogenation. Chem Pharm Bull (Tokyo) 2005; 53:1152-8. [PMID: 16141586 DOI: 10.1248/cpb.53.1152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
1,2-Dihydropyrazin-2-one derivatives, which have two aminoalkyl groups at the positions 3 and 6, were found to be efficient tools for the construction of potent, selective and long-acting opioid mimetics. During the course of preparation, we found that the catalytic hydrogenation of 3,6-bis(benzyloxycarbonylaminomethyl)-5-methyl-1,2-dihydropyrazin-2-one to remove the benzyloxycarbonyl groups resulted in a side reaction. By MS and NMR studies and by preparation of additional 1,2-dihydropyrazin-2-one derivatives, the structure of the by-product was identified as 3-aminomethyl-5,6-dimethyl-1,2-dihydropyrazin-2-one. Preparation of additional compounds substituted with deuterium provided us with sufficient information to confirm the structure of the product and to support a cyclization mechanism in its formation.
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Affiliation(s)
- Anna Miyazaki
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University; Nishi-ku, Kobe 651-2180, Japan
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8
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Igarashi K, Murabayashi Y, Hotta K, Kitamura Y, Kasuya F, Shiotani K, Tingyou L, Miyazaki A, Tsuda Y, Okada Y, Fukushima S. Application of liquid chromatography-tandem mass spectrometry for the determination of opioidmimetics in the brain dialysates from rats treated with opioidmimetics intraperitoneally. J Chromatogr B Analyt Technol Biomed Life Sci 2005; 806:53-7. [PMID: 15149611 DOI: 10.1016/j.jchromb.2004.02.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have determined three opioidmimetics (compounds I-III) in the rat brain dialysates after intraperitoneal (i.p.) administration of compounds I-III using a liquid chromatography/mass spectrometry with tandem mass spectrometry (LC-MS/MS). The dialysate samples with methanol were directly analyzed by online column-switching liquid chromatography. Using multiple reaction monitoring (MRM, product ions m/z 421 of m/z 657 for compound I, m/z 421 of m/z 643 for compound II, and m/z 407 of m/z 629 for compound III) on LC-MS/MS with electrospray ionization (ESI), opioidmimetics in rat brain dialysates were determined. Calibration curves of the method showed a good linearity in the range of 10-100 ng/ml for each compound. The limit of determination was estimated to be ca. 1 ng/ml for compounds II and III, and ca. 5 ng/ml for compound I, respectively. The precision of analysis showed coefficients of variation ranging from 4.7 to 10.4% at compound III concentration (10-100 ng/ml) in Ringer's solution. As a result, the procedure proved to be very suitable for routine analysis. The method was applied to the analysis of three opioidmimetics in the brain dialysate samples from rats treated with these compounds.
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Affiliation(s)
- Kazuo Igarashi
- Department of Analytical Toxicology, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan.
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9
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Design and synthesis of novel type somatostatin analogs with antiproliferative activities on A431 tumor cells. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.06.105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Bryant SD, Jinsmaa Y, Salvadori S, Okada Y, Lazarus LH. Dmt and opioid peptides: a potent alliance. Biopolymers 2004; 71:86-102. [PMID: 12767112 DOI: 10.1002/bip.10399] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The introduction of the Dmt (2',6'-dimethyl-L-tyrosine)-Tic pharmacophore into the design of opioid ligands produced an extraordinary family of potent delta-opioid receptor antagonists and heralded a new phase in opioid research. First reviewed extensively in 1998, the incorporation of Dmt into a diverse group of opioid molecules stimulated the opioid field leading to the development of unique analogues with remarkable properties. This overview will document the crucial role played by this residue in the proliferation of opioid peptides with high receptor affinity (K(i) equal to or less than 1 nM) and potent bioactivity. The discussion will include the metamorphosis between delta-opioid receptor antagonists to delta-agonists based solely on subtle structural changes at the C-terminal region of the Dmt-Tic pharmacophore as well as their behavior in vivo. Dmt may be considered promiscuous due to the acquisition of potent mu-agonism by dermorphin and endomorphin derivatives as well as by a unique class of opioidmimetics containing two Dmt residues separated by alkyl or pyrazinone linkers. Structural studies on the Dmt-Tic compounds were enhanced tremendously by x-ray diffraction data for three potent and biologically diverse Dmt-Tic opioidmimetics that led to the development of pharmacophores for both delta-opioid receptor agonists and antagonists. Molecular modeling studies of other unique Dmt opioid analogues illuminated structural differences between delta- and mu-receptor ligand interactions. The future of these compounds as therapeutic applications for various medical syndromes including the control of cancer-associated pain is only a matter of time and perseverance.
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Affiliation(s)
- Sharon D Bryant
- Peptide Neurochemistry, LCBRA, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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11
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Jinsmaa Y, Miyazaki A, Fujita Y, Li T, Fujisawa Y, Shiotani K, Tsuda Y, Yokoi T, Ambo A, Sasaki Y, Bryant SD, Lazarus LH, Okada Y. Oral Bioavailability of a New Class of μ-Opioid Receptor Agonists Containing 3,6-Bis[Dmt-NH(CH2)n]-2(1H)-pyrazinone with Central-Mediated Analgesia. J Med Chem 2004; 47:2599-610. [PMID: 15115401 DOI: 10.1021/jm0304616] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The inability of opioid peptides to be transported through epithelial membranes in the gastrointestinal tract and pass the blood-brain barrier limits their effectiveness for oral application in an antinociceptive treatment regime. To overcome this limitation, we enhanced the hydrophobicity while maintaining the aqueous solubility properties in a class of opioid-mimetic substances by inclusion of two identical N-termini consisting of Dmt (2',6'-dimethyl-l-tyrosine) coupled to a pyrazinone ring platform by means of alkyl chains to yield the class of 3,6-bis[Dmt-NH-(CH(2))(n)]-2(1H)-pyrazinones. These compounds displayed high micro-opioid receptor affinity (K(i)micro = 0.042-0.115 nM) and selectivity (K(i)delta/K(i)micro = 204-307) and functional micro-opioid receptor agonism (guinea-pig ileum, IC(50) = 1.3-1.9 nM) with little or undetectable bioactivity toward delta-opioid receptors (mouse vas deferens) and produced analgesia in mice in a naloxone reversible manner when administered centrally (intracerebroventricular, i.c.v.) or systemically (subcutaneously and orally). Furthermore, the most potent compound, 3,6-bis(3'-Dmt-aminopropyl)-5-methyl-2(1H)-pyrazinone (7'), lacked functional delta-opioid receptor bioactivity and was 50-63-fold and 18-21-fold more active than morphine by icv administration as measured analgesia using tail-flick (spinal involvement) and hot-plate (supraspinal effect) tests, respectively; the compound ranged from 16 to 63% as potent upon systemic injection. These analgesic effects are many times greater than unmodified opioid peptides. The data open new possibilities for the rational design of potential opioid-mimetic drugs that pass through the epithelium of the gastrointestinal tract and the blood-brain barrier to target brain receptors.
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Affiliation(s)
- Yunden Jinsmaa
- Medicinal Chemistry Group, LCBRA, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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12
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Okada Y, Tsuda Y, Fujita Y, Yokoi T, Sasaki Y, Ambo A, Konishi R, Nagata M, Salvadori S, Jinsmaa Y, Bryant SD, Lazarus LH. Unique high-affinity synthetic mu-opioid receptor agonists with central- and systemic-mediated analgesia. J Med Chem 2003; 46:3201-9. [PMID: 12852751 DOI: 10.1021/jm020459z] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Unique opioid mimetic substances containing identical N-terminal aromatic residues separated by an unbranched alkyl chain containing two to eight methylene groups were developed. Regardless of the length of interposing alkyl chain, the bis-Tyr and bis-Phe compounds were inactive; however, replacement by a single Dmt (2',6'-dimethyl-L-tyrosine) residue enhanced activity by orders of magnitude. Moreover, the bis-Dmt compounds were another 10-fold more potent with an optimum intra-aromatic ring distance of about four to six methylene units. 1,4-Bis(Dmt-NH)butane (7) had high mu-opioid receptor affinity (K(i) = 0.041 nM) and functional mu-opioid agonist bioactivity (IC(50) = 5.3 nM) with in vivo central (intracerebroventricular) and systemic (subcutaneous) analgesia in mice (1.5- to 2.5-fold greater than and 10-12% relative to morphine, respectively); these activities were reversed by naloxone to the same degree. It appears that the bis-Dmt compounds indiscriminately act as both message and address domains.
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Affiliation(s)
- Yoshio Okada
- Faculty of Pharmaceutical Sciences, Department of Medicinal Chemistry and High Technology Research Center, Kobe Gakuin University, Nishi-ku, Kobe 651-2180, Japan.
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Okada Y, Fujisawa Y, Morishita A, Shiotani K, Miyazaki A, Fujita Y, Li T, Tsuda Y, Yokoi T, Bryant SD, Lazarus LH. Immediate deamination from the aminomethyl group attached to 1,2-dihydropyrazin-2-one derivative during catalytic hydrogenation. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)01944-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Okada Y, Tsuda Y, Wanaka K, Tada M, Okamoto U, Okamoto S, Hijikata-Okunomiya A, Bokonyi G, Szende B, Keri G. Development of plasmin and plasma kallikrein selective inhibitors and their effect on M1 (melanoma) and HT29 cell lines. Bioorg Med Chem Lett 2000; 10:2217-21. [PMID: 11012033 DOI: 10.1016/s0960-894x(00)00431-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
trans-4-Aminomethylcyclohexanecarbonyl-Tyr(O-Pic)-octylamide (YO-2) inhibited plasmin (PL) selectively, while trans-4-aminomethylcyclohexanecarbonyl-Phe-4-carboxymethylanili de (YO-1) inhibited plasma kallikrein (PK). YO-2 induced apoptosis of M1 (melanoma) cell line and HT29 colon carcinoma cells during 24 h through activation of caspase-3, while YO-1 did not affect either cell line even during 48 h.
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Affiliation(s)
- Y Okada
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Japan.
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Okada Y, Fukumizu A, Takahashi M, Shimizu Y, Tsuda Y, Yokoi T, Bryant SD, Lazarus LH. Synthesis of stereoisomeric analogues of endomorphin-2, H-Tyr-Pro-Phe-Phe-NH(2), and examination of their opioid receptor binding activities and solution conformation. Biochem Biophys Res Commun 2000; 276:7-11. [PMID: 11006073 DOI: 10.1006/bbrc.2000.3416] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
All sixteen stereoisomeric analogues of endomorphin-2 (H-Tyr-Pro-Phe-Phe-NH(2)) were synthesized by Fmoc-strategy using solid phase methods. Although synthetic endomorphin-2 exhibited similar mu- and delta-opioid receptor-binding activity to the natural compound, endomorphin-2 analogues containing d-amino acid isomers exhibited lower interaction with mu-receptors depending on the particular combination. The data clearly indicated that the three dimensional structure of endomorphin-2 with the natural l-configuration was the most suitable for binding within the mu receptor, but specific residues are important for activity. Circular dichroism studies verified that changes in chirality of amino acids in the endomorphin-2 sequence resulted in structural conformation. These alterations significantly reduced the specificity for mu-receptor-binding sites.
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Affiliation(s)
- Y Okada
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Nishi-ku, Kobe, 651-2180, Japan.
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