Cyclohexy (4-fluorophenyl)(3-piperidinopropyl)silanol ((itp)-fluoro-hexahydro-sila-difenidol, p-F-HSSiD) and derivatives: synthesis and antimuscarinic properties
作者:Reinhold Tacke、Klaus Mahner、Carsten Strohmann、Bernhard Forth、Ernst Mutschler、Thomas Friebe、Günter Lambrecht
DOI:10.1016/0022-328x(91)80194-o
日期:1991.10
Four different syntheses of the potent and selective muscarinic antagonist cyclohexyl(4-fluorophenyl)(3-piperidinopropyl)silanol (p-fluoro-hexahydro-sila-difenidol, p-F-HHSiD (2b); isolated as hydrochloride 2b.HCl) are described (starting materials: (CH3O)3SiCH2CH2CH2Cl and Si(OCH3)4). In addition, the synthesis of the corresponding carbon analogue p-fluoro-hexahydro-difenidol (p-F-HHD (2a); isolated as 2a.HCl) and the syntheses of three p-F-HHSiD derivatives (3-5), with a modified cyclic amino group, are reported (3: piperidino/pyrrolidino exchange, isolated as 3.HCl; 4: piperidino/hexamethylenimino exchange, isolated as 4.HCl; 5: quaternization of 2b with methyl iodide). The chiral compounds 2a, 2b, 3, 4 and 5 were prepared as racemates. In functional pharmacological studies, 3-5 behaved as simple competitive antagonists at muscarinic M1 receptors in rabbit vas deferens, M2 receptors in guinea-pig atria, and M3 receptors in guinea-pig ileal smooth muscle. The pyrrolidino (3) and hexamethylenimino (4) analogues of the parent drug p-F-HHSiD (2b) displayed the highest affinity for M1 and M3 receptors (pA2 values: 7.0-7.4) but exhibited lower affinity for cardiac M2 receptors (pA2: 5.9 and 6.0). Their affinity profile (M1 approximately M3 > M2) is different from that of p-F-HHSiD (2b) (M3 > M1 > M2), but qualitatively very similar to that of p-F-HHD (2a). The methiodide 5 exhibited the highest affinity for M1 receptors (pA2: 8.5) but lower affinity for M2 and M3 receptors by factors of 5.6 and 3.6, respectively.