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  • 11
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Absolute Configuration of the Enantiomers of the Antimuscarinic Agents Procyclidine and Tricyclamol Iodide: X-Ray Structural Analysis of (R)-1-[3-Cyclohexyl-3-hydroxy-3-phenyl-propyl]-1-methylpyrrolidinium IodideThe absolute configurations of the antimuscarinic agents procyclidine (1a) and tricyclamol iodide (2a) were established by X-ray structural analysis of (R)-1-[3-Cyclohexyl-3-hydroxy-3-phenyl-propyl]-1-methylpyrrolidinium iodide [(R)-tricyclamol iodide, (R)-2a]. The antimuscarinic potency of (R)-1a and (R)-2a is about 380 and 90 times, respectively, greater than that of the corresponding (S)-configurated enantiomers (guinea-pig ileum).
    Notes: Durch Röntgenstrukturanalyse von (R)-1-[3-Cyclohexyl-3-hydroxy-3-phenylpropyl]-1-methyl-pyrrolidiniumiodid [(R)-Tricyclamoliodid, (R)-2a] wurden die absoluten Konfigurationen der Enantiomere der Antimuskarinika Procyclidin (1a) und Tricyclamoliodid (2a) bestimmt. (R)-1a und (R)-2a sind etwa 380-bzw. 90mal stärker antimuskarinisch wirksam (isoliertes Meerschweinchen-Ileum) als die entsprechenden (S)-konfigurierten Enantiomere.
    Additional Material: 2 Ill.
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  • 12
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sila-Pharmaca, 33.  -  Synthesis and Properties of the Selective Antimuscarinic Agent Cyclohexylphenyl(3-piperidinopropyl)silanolThe synthesis of the selective antimuscarinic agent cyclohexylphenyl(3-piperidinopropyl)silanol (1b) is described. Starting with (3-chloropropyl)trimethoxysilane, 1b was obtained by four reaction steps and isolated as hydrochloride 2b with a total yield of about 45%.  -  Because of its high pharmacological selectivity 1b has become a reference drug in experimental pharmacology for the differentiation of muscarinic receptors.
    Notes: Die Synthese des selektiven Antimuskarinikums Cyclohexylphenyl(3-piperidinopropyl)silanol (1b) wird beschrieben. 1b wurde - ausgehend von (3-Chlorpropyl)trimethoxysilan - durch eine vierstufige Reaktionsfolge erhalten und als Hydrochlorid 2b mit einer Gesamt-ausbeute von etwa 45% isoliert.  -  1b ist aufgrund seiner großen pharmakologischen Selektivität zu einer Standardsubstanz in der experimentellen Pharmakologie bei der Differenzierung von Muskarinrezeptoren geworden.
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  • 13
    ISSN: 0268-2605
    Keywords: o-methoxy-sila-hexocyclium ; sila-hexocyclium ; sila-drugs ; antimuscarinics ; muscarinic receptor subtypes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the potent and highly selective silicon-containing antimuscarinic agent o-methoxysila-hexocyclium methyl sulfate and its corresponding tertiary amine (isolated as the dihydrochloride) is described. The quarternary compound is an o-methoxy derivative of sila-hexocyclium methyl sulfate, which represents one of the tools currently used in experimental pharmacology for the subclassification of muscarinic receptors. The o-methoxy derivative, the pharmacological profile of which differs substantially from that of the nonmethoxy compound, is also recommended as a tool for the investigation of muscarinic receptor heterogeneity.
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  • 14
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sila-Pharmaca, 371). - Preparation and Properties of tbe Enantiomers of the Antimuscarinic Agents Sila-Procyclidine and Sila-Tricyclamol Iodide: optically Active Silanols with Silicon as the Centre of Chirality2)The enantiomers of sila-procyclidine (R)-1b and (S)-1b [ 〉 97% ee (NMR), 99.7% ee (DSC)] were obtained by resolution with L-(+)- and D-(-)-tartaric acid, respectively. Starting from (R)-1b and (S)-1b, the hydrochlorides (R)-2b and (S)-2b were prepared and the enantiomers of sila-tricyclamol iodide (R)-3b and (S)-3b [ 〉 96% ee (NMR)] were synthesized by reaction with CH3I. The optically active silanols show configurational stability in the crystalline state and in inert solvents, whereas they racemize in aqueous solution (3b faster than 1b). By analogy with the stereoselectivity of antimuscarinic action of the enantiomers of the carbon analogues procyclidine (1a) and tricyclamol iodide (3a), the (R) enantiomers of 1b and 3b show a greater affinity for the ileal M2β and atrial M2α muscarinic receptors of the guinea pig than the corresponding (S) antipodes. All silicon compounds exhibit a greater antimuscarinic potency than their carbon analogues, whereas the stereoselectivity of action is more pronounced for the carbon compounds. The differences in affinity for (R)-1b and (S)-1b for ileal and atrial muscarinic receptors confirm the present concept of heterogeneity in muscarinic M2 receptors (M2α: atrial type; M2β: ileal type).
    Notes: Durch Racematspaltung mit L-(+)- bzw. D-(-)-Weinsäure wurden die Enantiomere des Sila-Procyclidins (R)-1b und (S)-1b erhalten [〉 97% ee (NMR), 99.7% ee (DSC)]. Daraus wurden die Hydrochloride (R)-2b und (S)-2b und durch Umsetzung mit CH3I die Enantiomere des Sila-Tricyclamol-iodids (R)-3b und (S)-3b [ 〉 96% ee (NMR)] hergestellt. Die optisch aktiven Silanole sind in kristalliner Form und in inerten Lösungsmitteln konfigurationsstabil, während sie in wässeriger Lösung racemisieren (3b schneller als 1b). In Analogie zur Stereoselektivität der antimuskarinischen Wirkung der Enantiomere der Kohlenstoff-Analoga Procyclidin (1a) und Tricyclamol-iodid (3a) besitzen die (R)-Enantiomere von 1b und 3b eine größere Affinität zu den ilealen M2β- und atrialen M2α- Muskarinrezeptoren des Meerschweinchens als die (S)-Antipoden. Alle Silicium-Verbindungen sind stärker antimuskarinisch wirksam als ihre Kohlenstoff-Analoga, deren Stereoselektivität jedoch stärker ausgeprägt ist. Die Unterschiede in der Affinität von (R)-1b und (S)-1b zu den ilealen und atrialen Muskarinrezeptoren bestätigen das Konzept der Heterogenität muskarinischer M2-Rezeptoren (M2α: atrialer Typ; M2β: ilealer Typ).
    Additional Material: 2 Ill.
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  • 15
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sila-Pharmaca, 30. - (2-Aminoethyl)cycloalkylphenylsilanols: Bioisosteric C/Si Exchange in Parasympatholylics of the Trihexyphenidyl, Cycrimine, and Procyclidine TypeThe synthesis of the (2-aminoethyl)cycloakylphenylsilanols 5b (sila-trihexyphenidyl), 6b (Sila-cycrimine), 7b (sila-procyclidine), and 8b is described. Starting with CI2(C6H5)SiCh—CH2(9), 5b-8b were obtained by five reaction steps with a total yield of 32-40%. The C/Si pairs 5a,b-8a,b, were tested for antimuscarinic activity on the isolated guinea-pig ileum. The increase of affinity of the muscarinic receptor caused by sila-substitution of 5a-8a is less marked than in the case of the structurally related C/Si 1a,b-4a,b.
    Notes: Die Synthese der (2-Aminoethyl)cycloalkylphenylsilanole 5b (Sila-Trihexyphenidyl), 6b (Sila-Cycrimin), 7b (Sila-Procyclidin) und 8b wird beschrieben. 5b-8b wurden - ausgehend von Ci2(C?6H5)SiCCCCH—CH2 (9) - durch eine fünfstufige Reaktionsfolge mit einer Gesamtausbeute von 32-40% erhalten. Am isolierten Ileum des Meerschweinchens wurden die C/Si-Paare 5a,b-8a,b vergleichend auf ihre antimuskarinische Aktivität geprüft. Die durch die Sila-Substitution von 5a-8b erreichte Zunahme der Affinität zum Muskarinrezeptor ist deutlich weniger ausgeprägt als bei den strukturverwandten C/Si-Paaren 1a,b-4a,b.
    Additional Material: 1 Ill.
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  • 16
    ISSN: 0170-2041
    Keywords: Difenidol, (R)- and (S)-hexahydro- ; Antimuscarinic properties ; Muscarinic receptor subtypes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Properties of the Enantiomers of the Selective Antimuscarinic Agent 1-Cyclohexyl-1-phenyl-4-piperidino-1-butanol (Hexahydro-Difenidol)Using (S)- or (R)-mandelic acid as the resolving agent, the enantiomers of 1-cyclohexyl-1-phenyl-4-piperidino-2-butin-1-ol [(R)-2 and (S)-2] were prepared (enantiomeric purity: ee = 99.7%; calorimetric analysis). Catalytic hydrogenation (Pd/C contact) of (R)-2 and (S)-2 yielded the enantiomers of 1-cyclohexyl-1-phenyl-4-piperidino-1-butanol [(R)- and (S)-hexahydro-difenidol, (R)-1a and (S)-1a] which were isolated as hydrochlorides [(R)-1a ⋅ HCl and (S)-1a ⋅ HCl, ee = 99.7%]. The absolute configuration of the enantiomers of 1a and 2 was determined by an X-ray crystal structure analysis of the mandelate (S)-1a ⋅ (R)-C6H5CH(OH)COOH. (R)-Hexahydro-difenidol [(R)-1a] and (R)-2 exhibit a higher affinity for the atrial M2α and ileal M2β muscarinic receptors of the guinea pig than the respective antipodes (S)-1a and (S)-2 (atrial stereoselectivity index: 17 and 8.6, respectively; ileal stereoselectivity index: 193 and 44, respectively). In addition, (R)-1a and (R)-2 exhibit a significantly higher affinity for the M2β receptors of the ileum than for the M2α receptors of the atrium (atrium/ileum ratio: 21 and 10, respectively). Thus, (R)-1a and (R)-2 are valuable tools for the identification and characterization of muscarinic M2 subtypes. In contrast, the less potent (S)-enantiomers of 1a and 2 do not differentiate between M2α and M2β receptors.
    Notes: Durch Racematspaltung mit (S)- bzw. (R)-Mandelsäure wurden die Enantiomere von 1-Cyclohexyl-1-phenyl-4-piperidino-2-butin-1-ol [(R)-2 und (S)-2] dargestellt (Enantiomerenreinheit: ee = 99.7%, kalorimetrische Analyse). Katalytische Hydrierung (Pd/C-Kontakt) von (R)-2 und (S)-2 ergab die Enantiomere von 1-Cyclohexyl-1-phenyl-4-piperidino-1-butanol [(R)- und (S)-Hexahydro-Difenidol, (R)-1a und (S)-1a], die als Hydrochloride (R)-1a ⋅ HCl und (S)-1a ⋅ HCl isoliert wurden (ee = 99.7%). Die absolute Konfiguration der Enantiomere von 1a und 2 wurde durch Röntgenkristallstrukturanalyse des Mandelats (S)-1a ⋅ (R)-C6H5CH(OH)COOH bestimmt. (R)-Hexahydro-Difenidol [(R)-1a] und (R)-2 besitzen eine höhere Affinität zu den atrialen M2α-und ilealen M2β-Muscarinrezeptoren des Meerschweinchens als die entsprechenden Antipoden (S)-1a und (S)-2 (atrialer Stereoselektivitätsindex: 17 bzw. 8.6; ilealer Stereoselektivitätsindex: 193 bzw. 44). Darüber hinaus besitzen (R)-1a und (R)-2 eine signifikant höhere Affinität zu den M2β-Rezeptoren des Ileums als zu den M2α-Rezeptoren des Atriums und sind somit wertvolle Modellverbindungen zur Identifizierung und Charakterisierung von muscarinischen M2-Subtypen (Atrium/Ileum-Quotient: 21 bzw. 10). Im Gegensatz hierzu vermögen die schwächer wirksamen (S)-Enantiomere von 1a und 2 nicht zwischen den M2α- und M2β-Rezeptoren zu unterscheiden.
    Additional Material: 4 Ill.
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  • 17
    ISSN: 0170-2041
    Keywords: Difenidol, p-fluoro-hexahydro-, enantiomers of ; Muscarinic receptors, subtypes of ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantiomers of the antimuscarinic agent 1-cyclohexyl-1-(4-fluorophenyl)-4-piperidino-1-butanol [(R)- and (S)-p-fluorohexahydro-difenidol] [(R)- and (S)-2a] and their methiodides (R)-3 and (S)-3 were prepared with high enantiomeric purity. (R)-2a and (S)-2a (isolated as hydrochlorides) were obtained by catalytic hydrogenation (Pd/C contact) of the corresponding enantiomers of 1-cyclohexyl-1-(4-fluorophenyl)-4-piperidino-2-butyn-1-ol [(R)- and (S)-4]. Reaction of (R)-2a and (S)-2a with methyl iodide led to (R)-3 and (S)-3, respectively. The unsaturated precursors (R)- and (S)-4 (enantiomeric purity ≥99.80 and ≥99.94% e.e.; calorimetric analysis) were prepared by resolution of rac-4 [available from 4-FC6H4C(O)C6H11 by reaction with LiC≡CCH2NC5H10] using (R)- and (S)-mandelic acid as resolving agents. The absolute configurations of the (R) and (S) enantiomers of 2a, 3, and 4 were determined by an X-ray crystal-structure analysis of (S)-5, the methiodide of (S)-4. (R)-2a and (R)-3 exhibit a higher affinity for muscarinic M1, M2, M3, and M4 receptors (by up to two orders of magnitude) than their corresponding antipodes (S)-2a and (S)-3, the degree of stereoselectivity depending on the receptor subtype involved. (R)-2a represents a useful tool for muscarinic receptor research (affinity profile: M1 ≈ M3 ≈ M4 〉 M2).
    Additional Material: 2 Ill.
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