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Chemical Record (New York, N.Y.) Sep 2021The morphinans are an important class of structurally fascinating and physiologically important natural products as exemplified by the famous opium alkaloids of the... (Review)
Review
The morphinans are an important class of structurally fascinating and physiologically important natural products as exemplified by the famous opium alkaloids of the morphine family. Although this class of secondary metabolites from the juice of the opium poppy capsule was already used for medicinal purposes thousands of years ago, chemical modifications are still being applied to the core structure today in order to achieve the most specific effect on the various receptor subtypes possible with the fewest possible side effects. The unusual architecture of the morphinan core has also proven to be a highly challenging target for total synthesis. This review highlights electrosynthetic approaches towards natural and semisynthetic morphinan alkaloids. The historical progress in applying anodic aryl-aryl couplings to the construction of the morphinan framework is described in chronological order while particular benefits and challenges concerning the electrochemical transformations are grouped together, including the influence of substitution patterns, protecting groups, and reaction conditions.
Topics: Morphinans; Morphine; Papaver
PubMed: 33955153
DOI: 10.1002/tcr.202100078 -
Molecules (Basel, Switzerland) Jun 2023Opioids are considered the most effective analgesics for the treatment of moderate to severe acute and chronic pain. However, the inadequate benefit/risk ratio of... (Review)
Review
Opioids are considered the most effective analgesics for the treatment of moderate to severe acute and chronic pain. However, the inadequate benefit/risk ratio of currently available opioids, together with the current 'opioid crisis', warrant consideration on new opioid analgesic discovery strategies. Targeting peripheral opioid receptors as effective means of treating pain and avoiding the centrally mediated side effects represents a research area of substantial and continuous attention. Among clinically used analgesics, opioids from the class of morphinans (i.e., morphine and structurally related analogues) are of utmost clinical importance as analgesic drugs activating the mu-opioid receptor. In this review, we focus on peripheralization strategies applied to -methylmorphinans to limit their ability to cross the blood-brain barrier, thus minimizing central exposure and the associated undesired side effects. Chemical modifications to the morphinan scaffold to increase hydrophilicity of known and new opioids, and nanocarrier-based approaches to selectively deliver opioids, such as morphine, to the peripheral tissue are discussed. The preclinical and clinical research activities have allowed for the characterization of a variety of compounds that show low central nervous system penetration, and therefore an improved side effect profile, yet maintaining the desired opioid-related antinociceptive activity. Such peripheral opioid analgesics may represent alternatives to presently available drugs for an efficient and safer pain therapy.
Topics: Humans; Analgesics, Opioid; Morphinans; Pain; Analgesics; Morphine; Receptors, Opioid, mu
PubMed: 37375318
DOI: 10.3390/molecules28124761 -
Archives of Pharmacal Research Oct 2010Morphinans are a class of compounds containing the basic structure of morphine. It is well-known that morphinans possess diverse pharmacological effects on the central... (Review)
Review
Morphinans are a class of compounds containing the basic structure of morphine. It is well-known that morphinans possess diverse pharmacological effects on the central nervous system. This review will demonstrate novel neuroprotective effects of several morphinans such as, dextromethorphan, its analogs and naloxone on the models of multiple neurodegenerative disease by modulating glial activation associated with the production of a host of proinflammatory and neurotoxic factors, although dextromethorphan possesses neuropsychotoxic potentials. The neuroprotective effects and the therapeutic potential for the treatment of excitotoxic and inflammatory neurodegenerative diseases, and underlying mechanism of morphinans are discussed.
Topics: Animals; Astrocytes; Dextromethorphan; Humans; Morphinans; Naloxone; Neurodegenerative Diseases; Neuroglia; Neurons; Neuroprotective Agents
PubMed: 21052935
DOI: 10.1007/s12272-010-1009-4 -
Chemical Communications (Cambridge,... Nov 2018Here we report a total synthesis of the pharmacologically significant morphinan alkaloid, oxycodone. The centerpiece of the developed strategy features the first...
Here we report a total synthesis of the pharmacologically significant morphinan alkaloid, oxycodone. The centerpiece of the developed strategy features the first application of the Rovis desymmetrization of peroxyquinol in target-oriented total synthesis to access an optically active phenanthrene framework shared by the morphinans. A Stork-Ueno radical cyclization under photoredox conditions installed the all-carbon quaternary stereocenter, and a late-stage reductive detosylation with concomitant piperidine formation secured the core structure of the target molecule.
Topics: Cyclization; Light; Oxidation-Reduction; Oxycodone; Stereoisomerism
PubMed: 30394459
DOI: 10.1039/c8cc07667g -
Molecules (Basel, Switzerland) Apr 20226,14-ethenomorphinans are semisynthetic opiate derivatives containing an ethylene bridge between positions 6 and 14 in ring-C of the morphine skeleton that imparts a... (Review)
Review
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 20-etorphine and 20-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.
Topics: Analgesics; Analgesics, Opioid; Morphinans; Morphine; Naloxone; Receptors, Opioid; Receptors, Opioid, mu
PubMed: 35566212
DOI: 10.3390/molecules27092863 -
Journal of Medicinal Chemistry Jan 1974
Comparative Study
Topics: Analgesics; Animals; Drug Tolerance; Haplorhini; Mice; Morphinans; Nalorphine; Narcotic Antagonists; Pentazocine; Reaction Time; Stereoisomerism; Structure-Activity Relationship
PubMed: 4202213
DOI: 10.1021/jm00247a026 -
Bioorganic & Medicinal Chemistry Jul 2010Following indications from pharmacophore-based virtual screening of natural product databases, morphinan and isoquinoline compounds were tested in vitro for...
Following indications from pharmacophore-based virtual screening of natural product databases, morphinan and isoquinoline compounds were tested in vitro for acetylcholinesterase (AChE) inhibition. After the first screen, active and inactive compounds were used to build a ligand-based pharmacophore model in order to prioritize compounds for biological testing. Among the virtual hits tested, the enrichment of actives was significantly higher than in a random selection of test compounds. The most active compounds were biochemically tested for their activity on mu, delta, and kappa opioid receptors.
Topics: Acetylcholinesterase; Animals; Cholinesterase Inhibitors; Guinea Pigs; Isoquinolines; Models, Molecular; Morphinans; Rats; Receptors, Opioid
PubMed: 20580236
DOI: 10.1016/j.bmc.2010.05.071 -
Brain Research Apr 1988The non-narcotic dextrorotatory morphinan, dextrorphan, as well as its levorotatory opioid enantiomer, levorphanol, and its O-methyl derivative, dextromethorphan, have...
The non-narcotic dextrorotatory morphinan, dextrorphan, as well as its levorotatory opioid enantiomer, levorphanol, and its O-methyl derivative, dextromethorphan, have recently been shown to antagonize N-methyl-D-aspartate receptor-mediated neurotoxicity. Consistent with in vivo data suggesting that this neurotoxicity contributes to the neuronal damage associated with hypoglycemia, micromolar concentrations of these morphinans markedly attenuated the injury of cultured mouse cortical neurons produced by acute glucose deprivation. These observations lend specific support to the possibility that morphinan compounds may prove to have clinical therapeutic utility in hypoglycemic encephalopathy.
Topics: Animals; Cells, Cultured; Cerebral Cortex; Dextrorphan; Fetus; Glucose; Levorphanol; Mice; Morphinans; Neurons
PubMed: 3370477
DOI: 10.1016/0006-8993(88)91304-2 -
Drug and Alcohol Dependence Feb 1985The reinforcing properties of drugs can be evaluated pre-clinically using self-administration procedures in laboratory animals. This paper reviews self-administration... (Review)
Review
The reinforcing properties of drugs can be evaluated pre-clinically using self-administration procedures in laboratory animals. This paper reviews self-administration studies of the four opioid agonist/antagonist analgesics pentazocine, butorphanol, nalbuphine and buprenorphine, and compares these results to those from studies of morphine and cyclazocine. All four agonist/antagonists possess reinforcing properties under at least some test conditions. In this respect they more resemble morphine than cyclazocine. These results suggest that they all may have some potential for recreational use. On the other hand, some data point to a lower reinforcing efficacy for these agonist/antagonists than for the pure agonists such as morphine. Studies comparing the reinforcing efficacy among the agonist/antagonists are also reviewed, however more data are needed before definitive conclusions can be drawn within the class.
Topics: Animals; Buprenorphine; Butorphanol; Cyclazocine; Humans; Macaca mulatta; Morphinans; Morphine; Nalbuphine; Opioid-Related Disorders; Papio; Pentazocine; Rats; Reinforcement, Psychology; Self Administration
PubMed: 3888576
DOI: 10.1016/0376-8716(85)90060-2 -
Molecules (Basel, Switzerland) Sep 2021Adequate pain management, particularly chronic pain, remains a major challenge associated with modern-day medicine. Current pharmacotherapy offers unsatisfactory... (Review)
Review
Adequate pain management, particularly chronic pain, remains a major challenge associated with modern-day medicine. Current pharmacotherapy offers unsatisfactory long-term solutions due to serious side effects related to the chronic administration of analgesic drugs. Morphine and structurally related derivatives (e.g., oxycodone, oxymorphone, buprenorphine) are highly effective opioid analgesics, mediating their effects via the activation of opioid receptors, with the mu-opioid receptor subtype as the primary molecular target. However, they also cause addiction and overdose deaths, which has led to a global opioid crisis in the last decades. Therefore, research efforts are needed to overcome the limitations of present pain therapies with the aim to improve treatment efficacy and to reduce complications. This review presents recent chemical and pharmacological advances on 14-oxygenated--methylmorphinan-6-ones, in the search of safer pain therapeutics. We focus on drug design strategies and structure-activity relationships on specific modifications in positions 5, 6, 14 and 17 on the morphinan skeleton, with the goal of aiding the discovery of opioid analgesics with more favorable pharmacological properties, potent analgesia and fewer undesirable effects. Targeted molecular modifications on the morphinan scaffold can afford novel opioids as bi- or multifunctional ligands targeting multiple opioid receptors, as attractive alternatives to mu-opioid receptor selective analgesics.
Topics: Analgesics; Analgesics, Opioid; Animals; Morphinans; Receptors, Opioid, mu; Signal Transduction
PubMed: 34577147
DOI: 10.3390/molecules26185677