- 2,3,9- and 2,3,11-Trisubstituted tetrahydroprotoberberines as D2 dopaminergic ligands
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Dopamine-mediated neurotransmission plays an important role in relevant psychiatric and neurological disorders. Nowadays, there is an enormous interest in the development of new dopamine receptors (DR) acting drugs as potential new targets for the treatment of schizophrenia or Parkinson's disease. Previous studies have revealed that isoquinoline compounds such as tetrahydroisoquinolines (THIQs) and tetrahydroprotoberberines (THPBs) can behave as selective D2 dopaminergic alkaloids since they share structural similarities with dopamine. In the present study we have synthesized eleven 2,3,9- and 2,3,11-trisubstituted THPB compounds (six of them are described for the first time) and evaluated their potential dopaminergic activity. Binding studies on rat striatal membranes were used to evaluate their affinity and selectivity towards D1 and D2 DR and establish the structure-activity relationship (SAR) as dopaminergic agents. In general, all the tested THPBs with protected phenolic hydroxyls showed a lower affinity for D1 and D2 DR than their corresponding homologues with free hydroxyl groups. In previous studies in which dopaminergic affinity of 1-benzyl-THIQs (BTHIQs) was evaluated, the presence of a Cl into the A-ring resulted in increased affinity and selectivity towards D2 DR. This is in contrast with the current study since the existence of a chlorine atom into the A-ring of the THPBs caused increased affinity for D1 DR but dramatically reduced the selectivity for D2 DR. An OH group in position 9 of the THPB (9f) resulted in a higher affinity for DR than its homologue with an OH group in position 11 (9e) (250 fold for D2 DR). None of the compounds showed any cytotoxicity in freshly isolated human neutrophils. A molecular modelling study of three representative THPBs was carried out. The combination of MD simulations with DFT calculations provided a clear picture of the ligand binding interactions from a structural and energetic point of view. Therefore, it is likely that compound 9d (2,3,9-trihydroxy-THPB) behave as D2 DR agonist since serine residues cluster are crucial for agonist binding and receptor activation.
- Párraga, Javier,Cabedo, Nuria,Andujar, Sebastián,Piqueras, Laura,Moreno, Laura,Galán, Abraham,Angelina, Emilio,Enriz, Ricardo D.,Ivorra, María Dolores,Sanz, María Jesús,Cortes, Diego
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p. 150 - 166
(2013/10/01)
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- Synthesis of new antimicrobial pyrrolo[2,1-a]isoquinolin-3-ones
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The attractive structure of the pyrroloisoquinoline moiety, together with its potential antimicrobial activity, encouraged us to prepare six 8-substituted and seven 8,9-disubstituted-1,2,3,5,6,10b-hexahydropyrrolo[2,1-a]isoquinolin-3- ones in a few steps with good yields. We applied a convenient methodology via double intramolecular cyclization conducted by a Bischler-Napieralski cyclodehydration-imine reduction sequence, which is widely employed in the synthesis of isoquinoline alkaloids. Therefore, we synthesized three series of these pyrrolo[2,1-a]isoquinolin-3-ones characterized by the substituent at the 8-position or 8,9-positions of the aromatic ring: (a) different side chains are attached to an 8-OH group (series 1); (b) a chlorine atom is attached to the 8-position (series 2); and (c) 8- and 9-carbons are bearing an identical group (series 3). The compounds bearing a benzylic moiety at the 8-position, for example, 8-benzyloxy-pyrrolo[2,1-a]isoquinolin-3-one (1a) and 8-(4-fluorobenzyloxy)-pyrrolo[2,1-a]isoquinolin-3-one (1e), as well as, a 8-chloro-9-methoxy moiety including the 8-chloro-9-methoxy-pyrrolo[2,1-a] isoquinolin-3-one (2a), provided the most fungicide and bactericide agents, respectively.
- Moreno, Laura,Parraga, Javier,Galan, Abraham,Cortes, Diego,Cabedo, Nuria,Primo, Jaime
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p. 6589 - 6597,9
(2012/12/12)
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- Tetrahydroisoquinolines as dopaminergic ligands: 1-Butyl-7-chloro-6-hydroxy-tetrahydroisoquinoline, a new compound with antidepressant-like activity in mice
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Three series of 1-substituted-7-chloro-6-hydroxy-tetrahydroisoquinolines (1-butyl-, 1-phenyl- and 1-benzyl derivatives) were prepared to explore the influence of each of these groups at the 1-position on the affinity for dopamine receptors. All the compou
- Berenguer, Inmaculada,Aouad, Noureddine El,Andujar, Sebastian,Romero, Vanessa,Suvire, Fernando,Freret, Thomas,Bermejo, Almudena,Ivorra, Maria Dolores,Enriz, Ricardo D.,Boulouard, Michel,Cabedo, Nuria,Cortes, Diego
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experimental part
p. 4968 - 4980
(2009/12/04)
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- Cyclopentadienyltricarbonylrheniumbenzazepines: Synthesis and binding affinity
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Analogues of the benzazepine dopamine D1 receptor antagonist SCH-23390 incorporating the cyclo-pentadienyltricarbonyl-rhenium (CPTR) moiety were synthesized and evaluated pharmacologically. The CPTR derivatives retained affinity (0.3-2.9 nM) an
- Tamagnan, Gilles,Baldwin, Ronald M.,Kula, Nora S.,Baldessarini, Ross J.,Innis, Robert B.
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p. 1113 - 1115
(2007/10/03)
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- Quantitative structure-activity relationship modeling of dopamine D1 antagonists using comparative molecular field analysis, genetic algorithms- partial least-squares, and K nearest neighbor methods
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Several quantitative structure-activity relationship (QSAR) methods were applied to 29 chemically diverse D1 dopamine antagonists. In addition to conventional 3D comparative molecular field analysis (CoMFA), cross-validated R2 guided
- Hoffman, Brian,Cho, Sung Jin,Zheng, Weifan,Wyrick, Steven,Nichols, David E.,Mailman, Richard B.,Tropsha, Alexander
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p. 3217 - 3226
(2007/10/03)
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- (+/-)-(N-alkylamino)benzazepine analogs: novel dopamine D1 receptor antagonists.
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(+/-)-(N-Alkylamino)benzazepine analogs were prepared as novel dopamine D1 receptor antagonists to further elucidate the role of these receptor subtypes in the pharmacology and toxicology of cocaine. In the first series of compounds, (+/-)-7-chloro-8-hydroxy-3- [6-(N,N-dimethylamino)-hexyl]-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepi ne (15) showed the highest affinity (Ki = 49.3 nM) and subtype-selectivity for dopamine D1 over dopamine D2, 5-HT2a, and 5-HT2c receptors. Compounds 7a [(+/-)-7-Chloro-8-hydroxy-3-[4-(N,N-dimethylamino)butyl]-1-phenyl- 2,3,4,5-tetrahydro-1H-3-benzazepine], 11 [(+/-)-7-chloro-8-hydroxy-3-[6-[(N,N-dimethylamino)hexyl]-1- phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-cyanoborane], and 15 were moderately potent dopamine D1 receptor antagonists as evidenced by their ability to block dopamine-stimulated adenylyl cyclase activity in rat caudate (predicted Ki values = 60, 34, and 21 nM, respectively). Compound 7a appears to be unique in that, despite its relatively potent inhibition of dopamine stimulated adenylyl cyclase, it demonstrated relatively weak binding affinity at the dopamine D1 receptors (Ki = 811 nM). Unlike previously reported N-alkylbenzazepines, where a significant loss in dopamine D1 receptor binding affinity was observed when successive increases in the alkyl side chain size at the benzazepine nitrogen were made, several of these novel N-alkylamino analogs demonstrated high-affinity binding with an optimal chain length of six carbons. This initial series of compounds appears to be identifying another binding domain on the dopamine D1 receptor protein that has not previously been characterized and that accepts an amino function. Further, these compounds may serve as templates for the design of peripherally active dopamine D1 receptor antagonists.
- Shah,Izenwasser,Geter-Douglass,Witkin,Newman
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p. 4284 - 4293
(2007/10/03)
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- (±)-3-Allyl-7-halo-8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3- benzazepines as selective high affinity D1 dopamine receptor antagonists: Synthesis and structure-activity relationship
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Substituted 1-phenyl-3-benzazepines form a class of compounds possessing potent and selective affinity for the D1 DA receptor. 7,8-Dihydroxy-1-phenyl- 2,3,4,5-tetrahydro-1H-3-benzazepine (SKF 38393) and its 6-halo analogues are potent and selective D1 rec
- Baindur,Tran,Niznik,Guan,Seeman,Neumeyer
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- Dopamine receptor ligands and imaging agents
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Novel CNS dopamine D-1 receptors, such as the compound (.+-.)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-(4''-[ 125 I]iodophenyl)-1H-3-benzazepine-7-ol, are disclosed. These compounds are useful as imaging agents for D-1 receptors in the human brain and exhib
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- Synthesis and Resolution of (+/-)-7-Chloro-8-hydroxy-1-(3'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine (TISCH): A High Affinity and Selective Iodinated Ligand for CNS D1 Dopamine Receptor
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The synthesis and resolution of (+/-)-7-chloro-8-hydroxy-1-(3'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine, (+/-)-TISCH (8) has been achieved by resolution of intermediate 4, the O-methoxyl, 3'-bromo derivative, as the diastereomeric camphor
- Chumpradit, Sumalee,Kung, Mei-Pung,Billings, Jeffrey J.,Kung, Hank F.
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p. 877 - 883
(2007/10/02)
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- (+/-)-7-Chloro-8-hydroxy-1-(4'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine: A Potent CNS D-1 Dopamine Receptor Imaging Agent
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Synthesis, radiolabeling, and in vitro and in vivo properties of an iodinated benzazepine, (+/-)-7-chloro-8-hydroxy-1-(4'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine, FISCH, as a potential imaging agent for evaluation of centr
- Chumpradit, Sumalee,Kung, Hank F.,Billings, Jeffrey,Kung, Mei-Ping,Pan, Sangren
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p. 1431 - 1435
(2007/10/02)
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- Synthesis and pharmacological characterization of 1-phenyl-, 4-phenyl-, and 1-benzyl-1,2,3,4-tetrahydroisoquinolines as dopamine receptor ligands
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A series of 1-phenyl-, 4-phenyl-, and 1-benzyl-1,2,3,4-tetrahydroisoquinolines have been prepared as ring-contracted analogues of the prototypical D1 dopamine receptor antagonist SCH23390 [(R)-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3 benzazepine]. The affinity and selectivity of these isoquinolines for D1 receptors was determined by three biochemical endpoints in membrane homogenates prepared from rat corpus striatum: the potency to compete for [3H]SCH23390 binding sites; the potency to compete for [3H]spiperone (a D2 receptor ligand) binding sites; and effects on dopamine-stimulated adenylate cyclase. Competitive binding measurements at D1 sites showed SCH23390 to possess the highest affinity, followed by 1-phenyl > 1-benzyl > 4-phenyl for the isoquinolines. These results were highly correlated with the ability of the test compounds to antagonize dopamine-stimulated adenylate cyclase (r = 0.98). None of the compounds alone stimulated cAMP formation at concentrations of 10 nM to 100 μM. D2 competition binding showed the 1-benzyl derivative to possess the highest affinity, followed by 4-phenyl > SCH23390 > 1-phenyl. The tertiary 1-phenyl derivative was more potent than the secondary 1-phenyl analogue in all assays. Interestingly, resolution and single-crystal X-ray analysis of the tertiary N-methyl-1-phenyltetrahydroisoquinoline showed the most active enantiomer to possess the S absolute configuration, in contrast to the benzazepine (R)-SCH23390.
- Charifson,Wyrick,Hoffman,Ademe Simmons,Bowen,McDougald,Mailman
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p. 1941 - 1946
(2007/10/02)
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