Names | |
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Systematic IUPAC name (4E,5S)-4-Ethylidene-1,4,5,7-tetrahydro-2,5-ethanoazocino[4,3-b]inden-6(3H)-one | |
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CompTox Dashboard (EPA) | |
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Properties | |
C17H18N2O | |
Molar mass | 266.344 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Conolidine is an indole alkaloid. Preliminary reports suggest that it could provide analgesic effects with few of the detrimental side-effects associated with opioids such as morphine, though at present it has only been evaluated in mouse models.
Conolidine was first isolated in 2004 from the bark of the Tabernaemontana divaricata (crape jasmine) shrub which is used in traditional Chinese medicine. [1]
The first asymmetric total synthesis of conolidine was developed by Micalizio and coworkers in 2011. [2] This synthetic route allows access to either enantiomer (mirror image) of conolidine via an early enzymatic resolution. Notably, evaluation of the synthetic material resulted in the discovery that both enantiomers of the synthetic compound show analgesic effects. [3]
The Micalizio route (2011) achieved the end product in 9 steps from a commercially available acetyl-pyridine. Notable reactions include a [2,3]-Still-Wittig rearrangement and a conformationally-controlled intramolecular Mannich cyclization.
The Weinreb group (2014) used a conjugative addition of an indole precursor to an oxime-substituted nitrosoalkene to generate the tetracyclic skeleton of conolidine in 4 steps. [4]
Takayama and colleagues (2016) synthesized conolidine and apparicine through a gold(I)-catalyzed exo-dig synthesis of a racemic piperidinyl aldehyde. [5]
Ohno and Fujii (2016) accessed the tricyclic pre-Mannich intermediate through a chiral gold(I) catalyzed cascade cyclization. [6]
In 2019, a six step synthesis was developed using Gold-catalyzed cyclization reaction and Pictet-Spengler reaction having 19% overall yield. [7]
In 2011, the Bohn lab noted antinociception against both chemically induced and inflammation-derived pain, and experiments indicated lack of opioid receptor modulation, but were unable to define a particular target. A 2019 study by a cross-site Australian and U.S. group discovered through cultured neuronal networks that conolidine may inhibit the Ca v2.2 channel, a mechanism seen in molecules like conotoxin. The group was unable to rule out partial polypharmacology against other targets. [8]
Conolidine has been discovered to bind to novel opioid receptor ACKR3 (CXCR7). [9] [10] By binding to this receptor, the endogenous opioid peptides (such as endorphins and enkephalins) cannot be trapped thus increasing availability of those peptides to their target sites. [9] [10]
DS54360155, a novel compound with a unique and original bicyclic skeleton, is more a potent analgesic than conolidine in mice. [11] DS39201083 [12] and DS34942424 [13] are other similar derivatives. They all lack mu-opioid activity. The researchers who found conolidine binding site ACKR3/CKCR7 also developed a synthetic analogue of it called RTI-5152-12. It displays an even greater activity on that receptor. [9]
Salvinorin A is the main active psychotropic molecule in Salvia divinorum. Salvinorin A is considered a dissociative hallucinogen.
Salvinorins are a group of natural chemical compounds and their structural analogs. Several salvinorins have been isolated from Salvia divinorum. They are classified as diterpenoid furanolactones. Salvinorin A is a hallucinogen with dissociative effects.
The δ-opioid receptor, also known as delta opioid receptor or simply delta receptor, abbreviated DOR or DOP, is an inhibitory 7-transmembrane G-protein coupled receptor coupled to the G protein Gi/G0 and has enkephalins as its endogenous ligands. The regions of the brain where the δ-opioid receptor is largely expressed vary from species model to species model. In humans, the δ-opioid receptor is most heavily expressed in the basal ganglia and neocortical regions of the brain.
Metazocine is an opioid analgesic related to pentazocine. While metazocine has significant analgesic effects, mediated through a mixed agonist–antagonist action at the mu opioid receptor, its clinical use is limited by dysphoric and hallucinogenic effects which are most likely caused by activity at kappa opioid receptors and/or sigma receptors.
Herkinorin is an opioid analgesic that is an analogue of the natural product salvinorin A. It was discovered in 2005 during structure-activity relationship studies into neoclerodane diterpenes, the family of chemical compounds of which salvinorin A is a member.
Atypical chemokine receptor 3 also known as C-X-C chemokine receptor type 7 (CXCR-7) and G-protein coupled receptor 159 (GPR159) is a protein that in humans is encoded by the ACKR3 gene.
Tebanicline is a potent synthetic nicotinic (non-opioid) analgesic drug developed by Abbott. It was developed as a less toxic analog of the potent poison dart frog-derived compound epibatidine, which is about 200 times stronger than morphine as an analgesic, but produces extremely dangerous toxic side effects. Like epibatidine, tebanicline showed potent analgesic activity against neuropathic pain in both animal and human trials, but with far less toxicity than its parent compound. It acts as a partial agonist at neuronal nicotinic acetylcholine receptors, binding to both the α3β4 and the α4β2 subtypes.
Epiboxidine is a chemical compound which acts as a partial agonist at neural nicotinic acetylcholine receptors, binding to both the α3β4 and the α4β2 subtypes. It was developed as a less toxic analogue of the potent frog-derived alkaloid epibatidine, which is around 200 times stronger than morphine as an analgesic but produces extremely dangerous toxic nicotinic side effects.
Azaprocin is a drug which is an opioid analgesic with approximately ten times the potency of morphine, and a fast onset and short duration of action. It was discovered in 1963, but has never been marketed.
J-113,397 is an opioid drug which was the first compound found to be a highly selective antagonist for the nociceptin receptor, also known as the ORL-1 receptor. It is several hundred times selective for the ORL-1 receptor over other opioid receptors, and its effects in animals include preventing the development of tolerance to morphine, the prevention of hyperalgesia induced by intracerebroventricular administration of nociceptin, as well as the stimulation of dopamine release in the striatum, which increases the rewarding effects of cocaine, but may have clinical application in the treatment of Parkinson's disease.
YM-348 is an indazole derivative drug which acts as a potent and selective 5-HT2C receptor agonist, with an EC50 of 1nM and 15x selectivity over 5-HT2A, although it only has moderate selectivity of 3x over the closely related 5-HT2B receptor. It has thermogenic and anorectic effects in animal studies, making it potentially useful for the treatment of obesity.
Org 28312 is a drug developed by Organon International which acts as a potent cannabinoid receptor full agonist at both the CB1 and CB2 receptors. It was developed with the aim of finding a water-soluble cannabinoid agonist suitable for intravenous use as an analgesic, but did not proceed to human trials, with the related compound Org 28611 chosen instead due to its better penetration into the brain. The structure-activity relationships of these compounds have subsequently been investigated further leading to the development of a number of more potent analogues, derived by cyclisation around the indole or piperazine rings.
MT-45 (IC-6) is an opioid analgesic drug invented in the 1970s by Dainippon Pharmaceutical Co. It is chemically a 1-substituted-4-(1,2-diphenylethyl) piperazine derivative, which is structurally unrelated to most other opioid drugs. Racemic MT-45 has around 80% the potency of morphine, with almost all opioid activity residing in the (S) enantiomer. It has been used as a lead compound from which a large family of potent opioid drugs have been developed, including full agonists, partial agonists, and antagonists at the three main opioid receptor subtypes. Fluorinated derivatives of MT-45 such as 2F-MT-45 are significantly more potent as μ-opioid receptor agonists, and one of its main metabolites 1,2-diphenylethylpiperazine also blocks NMDA receptors.
JWH-302 (1-pentyl-3-(3-methoxyphenylacetyl)indole) is an analgesic chemical from the phenylacetylindole family, which acts as a cannabinoid agonist with moderate affinity at both the CB1 and CB2 receptors. It is a positional isomer of the more common drug JWH-250, though it is slightly less potent with a Ki of 17 nM at CB1, compared to 11 nM for JWH-250. Because of their identical molecular weight and similar fragmentation patterns, JWH-302 and JWH-250 can be very difficult to distinguish by GC-MS testing.
IBNtxA, or 3-iodobenzoyl naltrexamine, is an atypical opioid analgesic drug derived from naltrexone. In animal studies it produces potent analgesic effects that are blocked by levallorphan and so appear to be μ-opioid mediated, but it fails to produce constipation or respiratory depression, and is neither rewarding or aversive in conditioned place preference protocols. These unusual properties are thought to result from agonist action at a splice variant or heterodimer of the μ-opioid receptor, rather than at the classical full length form targeted by conventional opioid drugs.
Apparicine is a monoterpenoid tricyclic indole alkaloid. It is named after Apparicio Duarte, a Brazilian botanist who studied the Aspidosperma species from which apparicine was first isolated. It was the first member of the vallesamine group of indole alkaloids to be isolated and have its structure established, which was first published in 1965. It has also been known by the synonyms gomezine, pericalline, and tabernoschizine.
HS665 is a drug which acts as a potent and selective κ-opioid receptor agonist, and has analgesic effects in animal studies. HS665 is not an agonist for the mu receptor, leading to less potential for abuse.
LIH383 is an octapeptide and highly potent and selective agonist of the atypical chemokine receptor ACKR3 (CXCR7) that was derived from the opioid peptide adrenorphin. ACKR3 is a novel opioid receptor which functions as a broad-spectrum trap or scavenger for endogenous opioid peptides, including enkephalins, dynorphins, and nociceptin, and thereby acts as a negative modulator of the opioid system. By displacing them from ACKR3 and thereby increasing their availability, LIH383 potentiates the actions of endogenous opioids, for instance their analgesic effects. Other ligands of ACKR3 include conolidine, CCX771, RTI-5152-12, and VUF15485.
RTI-5152-12, or WW-12, is a synthetic small-molecule agonist of the atypical chemokine receptor ACKR3 (CXCR7) that was derived from the naturally occurring alkaloid conolidine. RTI-5152-12 has 15-fold improved potency towards ACKR3 relative to conolidine.