Structure-activity studies of morphine fragments. III. Synthesis, opiate receptor binding, analgetic activity and conformational studies of spiro-[tetralin-1,4′-piperidines]
摘要:
A series of 5 spiro compounds, a new class of conformationally restricted analogs of 4-alkyl-4-(m-OH-phenyl) piperidines, have been synthesized and their affinities for mu, delta and kappa-opioid receptor sites and in vivo analgetic activities determined. All compounds show rather low affinities for the 3 receptors, with some modulation by the N-substituent and by the position of the phenolic group. To help understand the origin of this poor affinity compared to the unrestricted 4-alkyl-4-phenyl piperidines, energy conformation calculations were performed which indicated that all the analogs favor a phenyl equatorial over a phenyl axial conformer. Significant differences in the lowest energy conformation were found between these spiro analogs and both morphine and 4-n-propyl-4-(m-OH-phenyl) piperidines, 18 and 19 which are conformationally unrestricted, closely related analogs with high mu-affinity. These differences could account for their lower affinities. To continue the search for more active members of the family, structure variations which favor a phenyl-axial conformation have been identified and proposed for further study.
A simple and efficient process for the large scale preparation of agomelatine, an antidepressant drug is described. Agomelatine was synthesized from 7-methoxy-1-tetralone in five steps. The route reported employs readily, commercially viable starting materials, reagents and potentially be utilized for the process of synthesis of agomelatine.