Some Relationships Between Chemical Structure and Pharmacological Activities

Abstract

Earlier reviews in this series dealt with some relationships of chemical structure with biological activities (1-3) i the present assignment is restricted essentially to pharmacologically active compounds. As with the earlier re views, the published literature is not covered exhaustively, but some new re ports and observations are included which appeared from about September, 1964 [termination of coverage of last review (1)] to May, 1967. Where useful for purposes of relationship, selected older literature is cited.Over the years attempts have been made to devise general hypotheses pertaining to structure-activity relationships (SAR) and drug mechanisms of action. Recent efforts include variations of receptor occupancy hypotheses (Ariens, Stephenson), rate or kinetic hypotheses (Paton), and more chemi cally descriptive concepts (Belleau and others). In reviewing publications of the past two years that could be considered pertinent to SAR, one is im pressed by the gulf that exists between most synthesizers of new molecules and the developers of general hypotheses. For example, from 310 complete articles published in J. Med. Chern. (1965-66), only six made reference to these hypotheses either as stimuli for the project or as vehicles for cor relating SAR. This might indicate that the hypotheses are sterile or inade quate for either predictive or correlative purposes or that there is little in terest or inclination among most investigators in relating specific observa tions to general hypotheses. Most of these hypothes,t!s have indeed offered little that is of substantive value from a chemical perspective of devising novel molecules of biological interest. However, the efforts are commendable and some of these hypotheses may evolve and develop into theories with use ful correlative and predictive values. As hypotheses become more chemically descriptive, one can anticipate that there will be a greater consideration of such hypotheses by the designers of new, biologically interesting molecules.Their more recent concepts have been summarized by Ariens (4) and Paton (5). Shortcomings of the Ariens and Stephenson receptor occupancy and the Paton rate hypotheses have been analyzed by Belleau (6) as back ground for discussion of his "conformational perturbation" hypothesis.Bloom & Goldman (7) further consider these and modify and extend some of Belleau's views in proposing a "dynamic receptor hypothesis" relevant to catecholamine-adenine mononucleotide interactions in adrenergic mech anisms. These reviews are recommended to the cautious reader; space does 39 Annu. Rev. Pharmacol. 1968.8:39-66. Downloaded from www.annualreviews.org Access provided by New York University -Bobst Library on 05/14/15. For personal use only.Quick links to online content Further ANNUAL REVIEWS

Structure-Activity Relationships in the Adrenergic-Blocking Agents

“…It has been emphasized that this classification of the adrenergic receptors into two types agrees well with the antagonists of catecholamines much more than with the amines themselves (18). The element of uncertainty that lies in fitting metabolic, intestinal, cardiac, and CNS effects of catecholamines into this scheme is a challenge in itself, and there is no clear evidence as to whether differences between alpha-and beta-receptors are related t o basic structural features, to flexible conformational variants, or to relative accessibility of receptors (19). The evolution of alpha-and beta-receptor-blocking agents, a term coined by Moran and Perkins (20), in the last two decades is the immediate consequence of Ahlquist's classification.…”