Synthesis of 3-(5-bromo-2,3-dimethoxy-phenyl)-[1, 2, 4] oxadiazole analogues and their evaluation as anti-Parkinson′s agents
摘要:
A series of 3-(5-bromo-2,3-dimethoxy-phenyl)-[1, 2, 4] oxadiazole derivatives was prepared and their evaluation for anti-Parkinson's activity was measured in vivo using albino rats. The result of the biological activity studies indicated that some of the synthesized compounds have good agonistic activity on the dopamine receptors and a few of them were also found to be free from neurotoxicity. Thus these compounds might be useful ligands for studying the functional role of dopamine receptors in vivo. The high log P value of the compounds indicates that they should easily cross the blood-brain barrier (log P > 2.6).
Construction of Hydroxylated Alkaloids (.+-.)-Mannonolactam, (.+-.)-Deoxymannojirimycin, and (.+-.)-Prosopinine through Aza-Annulation
摘要:
The aza-annulation of beta enamino carbonyl substrates with acrylate derivatives provides an efficient and convenient route for the regioselective construction of delta-lactams. This two-step ring-forming sequence involved initial generation of the benzyl enamine through either a condensation or conjugate addition reaction with BnNH(2), followed by aza-annulation with acryloyl chloride or acrylic anhydride. Controlled by the rigid framework of the intermediate lactam, introduction of ring substituents was accomplished with high relative stereoselectivity. The carbonyl functionality, which was necessary to direct the regioselectivity of the aza-annulation reaction, was then transformed into a protected hydroxyl substituent through Baeyer-Villiger oxidation. The resultant delta-lactam product was used as a valuable intermediate in the synthesis of three natural products. Subsequent modification of this delta-lactam gave the naturally occurring alpha-mannosidase inhibitors (+/-)-mannonolactam and (+/-)deoxymannojirimycin, while synthesis of the alkaloid (+/-)-prosopinine was accomplished through homologation of the lactam carbonyl.
Synthesis of 2-(2,3-dimethoxyphenyl)-4-(aminomethyl)imidazole analogues and their binding affinities for dopamine D2 and D3 receptors
作者:Yunsheng Huang、Robert R Luedtke、Rebekah A Freeman、Li Wu、Robert H Mach
DOI:10.1016/s0968-0896(01)00175-4
日期:2001.12
same region resulted in a total loss of affinity for both dopamine receptor subtype binding sites. The most selective compound in this series is 2-(5-bromo-2,3-dimethoxyphenyl)-4-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolinomethyl)imidazole (5i), which has a D(3) receptor affinity of 21nM and a 7-fold selectivity for D(3) versus D(2) receptors. The binding affinity for sigma(1) and sigma(2) receptors was