84199-92-8Relevant articles and documents
Nα-Imidazolylalkyl and Pyridylalkyl Derivatives of Histaprodifen: Synthesis and in Vitro Evaluation of Highly Potent Histamine H1-Receptor Agonists
Menghin, Sonja,Pertz, Heinz H.,Kramer, Kai,Seifert, Roland,Schunack, Walter,Elz, Sigurd
, p. 5458 - 5470 (2007/10/03)
A novel series of Nα-imidazolylalkyl and pyridylalkyl derivatives of histaprodifen (6, 2-[2-(3,3-diphenylpropyl)imidazol-4-yl]ethanamine) was synthesized and evaluated as histamine H1-receptor agonists. The title compounds displayed partial agonism at contractile H1-receptors of guinea pig ileum and were at least equipotent with histamine. Agonist effects of the new derivatives were susceptible to blockade by the H1-receptor antagonist mepyramine (2-100 nM). In the imidazole series, suprahistaprodifen (51, [2-[2-(3,3-diphenylpropyl)-1H-imidazol-4-yl]ethyl]-[2-(1H-imidazol-4-yl) ethyl]amine, Nα-2-[(1H-imidazol-4-yl)ethyl]histaprodifen) showed the highest H1-receptor agonist potency ever reported in the literature (pEC50 8.26, efficacy Emax 96%). Elongation of the alkyl spacer from ethyl to butyl decreased activity from 3630% (ethyl, 51) to 163% (butyl, 53) of histamine potency. The exchange of the terminal imidazole nucleus for a pyridine ring resulted in compounds with comparably high potency. A decrease in agonist potency and efficacy was observed when the attachment of the alkyl spacer was consecutively changed from the ortho to the meta and the para position, respectively, of the pyridine ring. The pyridine series that contained a butyl chain possessed the highest potency and affinity. Nα-[4-(2-pyridyl)butyl]histaprodifen (56) emerged as a strong partial agonist, being almost equipotent with 51 (pEC50 8.16, E max 89%). Compounds 51 and 56 also showed potent partial agonism at contractile H1 receptors in guinea pig aorta and potently activated H1-receptor-mediated endothelium-dependent relaxation in the rat aorta. Compounds 51-65 displayed low to moderate affinity at H2, H3, and M3 receptors in functional models of guinea pig. Collectively, Nα-imidazolylalkyl- and Nα -pyridylalkyl-substituted histaprodifens represent a novel class of potent H1-receptor agonists. These compounds may be useful to define the (patho)physiological role of the H1-receptor and refine molecular models of H1-receptor activation.
Ring opening of cyclopropanemonocarboxylates and 1,1- cyclopropanedicarboxylates using samarium(II) diiodide (SmI2)-HMPA-THF system
Yamashita,Okuyama,Ohhara,Kawasaki,Sakai,Nakata,Kawabe,Kusumoto,Ohta
, p. 2075 - 2081 (2007/10/03)
The cyclopropane ring in 2-substituted 1,1-cyclopropanedicarboxylates was regioselectively opened by using samarium(II) diiodide (Sml2) in a hexamethylphosphoric triamide (HMPA)-tetrahydrofuran (THF) (1:10) system under mild and neutral conditions to give (2-substituted ethyl)malonates in moderate to good yields. The cyclopropane ring in 2-substituted cyclopropanecarboxylates or 2-substituted 3- (trimethylsilyl)cyclopropanecarboxylates was similarly cleaved regioselectively by using Sml2 in a HMPA-THF (1:1) system to give 4- arylbutyrates or 4-aryl-3-(trimethylsilyl)butyrates in 16-89% yields. The reaction mechanism of these ring-opening reactions is discussed.
ISOMERIZING RECYCLIZATION OF QUATERNARY SALTS OF ETHYL 3-(2-PYRIDYL)BUTYRATE AND DIETHYL 2-(2-PYRIDYL)ETHYLMALONATE
Ignatchenko, A. V.,Terent'ev, P. B.
, p. 292 - 295 (2007/10/02)
A number of quaternary salts of ethyl γ-pyridylbutyrate and diethyl β-pyridylethylmalonate undergo the Kost-Sagitullin reaction to give N-methyl-2-quinolone and 3-methylaminocarbamoyl-N-methyl-2-quinolone.Rearrangement in the presence of excess aliphatic amines is accompanied by an efficiently proceeding trans-amination.
