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Diels–Alder Adducts of Morphinan-6,8-Dienes and Their Transformations. Molecules 2022; 27:molecules27092863. [PMID: 35566212 PMCID: PMC9102320 DOI: 10.3390/molecules27092863] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 02/04/2023] Open
Abstract
6,14-ethenomorphinans are semisynthetic opiate derivatives containing an ethylene bridge between positions 6 and 14 in ring-C of the morphine skeleton that imparts a rigid molecular structure. These compounds represent an important family of opioid receptor ligands in which the 6,14-etheno bridged structural motif originates from a [4 + 2] cycloaddition of morphinan-6,8-dienes with dienophiles. Certain 6,14-ethenomorphinans having extremely high affinity for opioid receptors are often non-selective for opioid receptor subtypes, but this view is now undergoing some revision. The agonist 20R-etorphine and 20R-dihydroetorphine are several thousand times more potent analgesics than morphine, whereas diprenorphine is a high-affinity non-selective antagonist. The partial agonist buprenorphine is used as an analgesic in the management of post-operative pain or in substitution therapy for opiate addiction, sometimes in combination with the non-selective antagonist naloxone. In the context of the current opioid crisis, we communicated a summary of several decades of work toward generating opioid analgesics with lesser side effects or abuse potential. Our summary placed a focus on Diels–Alder reactions of morphinan-6,8-dienes and subsequent transformations of the cycloadducts. We also summarized the pharmacological aspects of radiolabeled 6,14-ethenomorphinans used in molecular imaging of opioid receptors.
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Choi H, Shirley HJ, Aitken HRM, Schulte T, Söhnel T, Hume PA, Brimble MA, Furkert DP. Intermolecular Diels-Alder Cycloaddition/Cross-Coupling Sequences of 2-Bromo-1,3-butadienes. Org Lett 2020; 22:1022-1027. [PMID: 31990192 DOI: 10.1021/acs.orglett.9b04567] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
2-Bromo-1,3-butadienes are demonstrated to be effective substrates for tandem Diels-Alder/transition metal cross-coupling reaction sequences. Intermolecular cycloaddition of a 2-bromo-1,3-diene with activated dienophiles proceeded under Lewis acid catalysis in generally high yields with good to excellent endo diastereoselectivity. The resulting vinyl bromide cycloadducts underwent subsequent Stille and Suzuki cross-couplings under standard conditions in good yields. Both the Diels-Alder and cross-coupling steps were highly tolerant of a range of functionalities and protecting groups. The use of the bromine substituent as both a cycloaddition directing group and cross-coupling nucleofuge avoids extra steps required to install and remove the more commonly used silyl enol ethers and enol sulfonates for each transformation and gives full control of the alkene regiochemistry throughout the reaction sequence. The 2-bromo-1,3-dienes were conveniently prepared in three steps from readily available aldehydes and established as hydrolytically stable and practical synthetic intermediates.
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Affiliation(s)
- Hans Choi
- School of Chemical Sciences , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand
| | - Harry J Shirley
- School of Chemical Sciences , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand
| | - Harry R M Aitken
- School of Chemical Sciences , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand
| | - Tim Schulte
- School of Chemical Sciences , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand
| | - Tilo Söhnel
- School of Chemical Sciences , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand
| | - Paul A Hume
- School of Chemical and Physical Sciences , Victoria University of Wellington , Kelburn Parade , Wellington 6012 , New Zealand
| | - Margaret A Brimble
- School of Chemical Sciences , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand
| | - Daniel P Furkert
- School of Chemical Sciences , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery , The University of Auckland , Symonds Street , Auckland 1010 , New Zealand
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Woudenberg RH, Meuzelaar GJ, Maat L. Synthesis of 7-substituted 6-demethoxythebaines and Diels-Alder reaction of 7-methoxy-5β-methyl-6-demethoxythebaine (chemistry of opium alkaloids, part XLI). ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19931121104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Meuzelaar GJ, Woudenberg RH, Sinnema A, Maat L. Synthesis of neopine and its 5β- and 7-substituted derivatives (chemistry of opium alkaloids, part XL≠). ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19931121103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sipos A, Debreceni S, Szabó R, Gyulai Z, Berényi S. Synthesis of 3‐Alkyl and Arylapomorphines. SYNTHETIC COMMUN 2007. [DOI: 10.1080/00397910701462773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Wu H, Bernard D, Chen W, Strahan GD, Deschamps JR, Parrish DA, Lewis JW, MacKerell AD, Coop A. Functionalization of the 6,14-bridge of the orvinols. 2. Preparation of 18- and 19-hydroxyl-substituted thevinols and their treatment with benzyl bromide. J Org Chem 2005; 70:1907-10. [PMID: 15730320 DOI: 10.1021/jo048388u] [Citation(s) in RCA: 9] [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
The etheno bridge of a thevinone was treated with BH3 and H2O2 to give both the 18- and 19-hydroxyl- substituted thevinols. Selective benzylation of the primary 20-hydroxyl over the 19-hydroxyl was successful; however, benzylation of the 18-hydroxylated product led to a reaction at the more hindered alcohol. Thus, the 6,14-bridge of the Diels-Alder products of thebaine can be hydroxylated, which opens up these positions for further chemical manipulation.
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Affiliation(s)
- Huifang Wu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Room 637, Baltimore, Maryland 21201, USA
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Chen W, Parrish D, Deschamps J, Coop A. Functionalization of the 6,14-Bridge of the Orvinols. Helv Chim Acta 2005. [DOI: 10.1002/hlca.200590060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Maat L, Woudenberg RH, Meuzelaar GJ, Linders JT. Chemistry of opium alkaloids. Part 44: synthesis and opioid receptor binding profile of substituted ethenoisomorphinans and ethenomorphinans. Bioorg Med Chem 1999; 7:529-41. [PMID: 10220038 DOI: 10.1016/s0968-0896(98)00267-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
7- and 8-substituted 6alpha,14alpha-ethenoisomorphinans were synthesized by reaction of properly substituted morphinan-6,8-dienes (analogues of thebaine) with methyl vinyl ketone or ethyl acrylate. Reaction with the appropriate Grignard reagent gave the 7- and 8-dialkylmethanols, respectively. Cleavage of the 3-methyl ether with KOH/glycol or boron tribromide afforded the 3-hydroxyl derivatives. In general, the compounds with the ethoxycarbonyl or dimethylmethanol substituent at the 8alpha-position showed lower affinity for the mu, kappa, and delta opioid receptor subtypes than the corresponding 7alpha- and 7beta-substituted compounds. Introduction of a chloro substituent in position 18 increased the potency significantly. The 7-substituent could be connected to the 18-position without loss of affinity. 5Beta-alkyl substitution of 6alpha,14alpha-ethenoisomorphinans led to a decrease in affinity for the three opioid receptor subtypes. In the 5beta-methyl series the affinity for the mu and delta receptors increased from 7alpha-dimethylmethanol to 7alpha-methylhexylmethanol. In the 5beta-alkyl series, the affinity for the mu-receptor could be increased by connecting the 5- and 7-substituents, yielding a compound with high mu-selectivity. The new 6beta,14beta-ethenomorphinans did not show affinity for any of the opioid receptors, in accordance with the inactivity earlier found in in vivo experiments.
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Affiliation(s)
- L Maat
- Laboratory of Organic Chemistry and Catalysis, Delft University of Technology, The Netherlands.
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Baas JMA, Woudenberg RH, Maat L. Chemistry of Opium Alkaloids, XLIII – A PM3 Computational Approach to the Selectivity in the Diels-Alder Reactions of Thebaine and Analogues with Methyl Propenoate. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jlac.199719970105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Berényi S, Sepsi Á, Gyulai S, Szilágyi L. Synthesis of Sulfur-Containing Morphinane Dienes. SYNTHETIC COMMUN 1995. [DOI: 10.1080/00397919508013849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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