Showing papers on "Pharmacophore published in 1987"
TL;DR: By placing the carboxyl binding group, the binding site for amido carbonyl, and the Zn atom site in positions determined by ideal binding geometry with the inhibitors' functional groups, it was possible to clearly specify a geometry for the active site of ACE.
Abstract: Previous structure-activity studies of captopril and related active angiotensin-converting enzyme (ACE) inhibitors have led to the conclusion that the basic structural requirements for inhibition of ACE involve (a) a terminal carboxyl group; (b) an amido carbonyl group; and (c) different types of effective zinc (Zn) ligand functional groups. Such structural requirements common to a set of compounds acting at the same receptor have been used to define a pharmacophoric pattern of atoms or groups of atoms mutually oriented in space that is necessary for ACE inhibition from a stereochemical point of view. A unique pharmacophore model (within the resolution of approximately 0.15 A) was observed using a method for systematic search of the conformational hyperspace available to the 28 structurally different molecules under study. The method does not assume a common molecular framework, and, therefore, allows comparison of different compounds that is independent of their absolute orientation. Consequently, by placing the carboxyl binding group, the binding site for amido carbonyl, and the Zn atom site in positions determined by ideal binding geometry with the inhibitors' functional groups, it was possible to clearly specify a geometry for the active site of ACE.
144 citations
TL;DR: A direct comparison of the antimicrobial and cytotoxic properties of a complete set of streptonigrin and lavendamycin partial structures is detailed in efforts to define the role peripheral substituents play in potentiating the biological properties of the naturally occurring and synthetic agents bearing the 7-aminoquinoline-5,8-dione AB ring system.
Abstract: The preparation and evaluation of 7-amino-5,8-dioxo-2-(2'-pyridyl)quinoline-6'-carboxylic acid (5a) and 7-amino-2-(2'-aminophenyl)-5,8-dioxoquinoline-5'-carboxylic acid (6a) constituting potential minimum, potent pharmacophores of streptonigrin (1a) and lavendamycin (2a), two structurally related naturally occurring antitumor antibiotics, are detailed. In contrast to observations associated with streptonigrin and lavendamycin in which the C-ring C-6' carboxylic acid potentiates the antitumor, antimicrobial, and cytotoxic properties of the naturally occurring, substituted 7-aminoquinoline-5,8-dione AB ring systems, the C-6'/C-5' carboxylic acid of 5a/6a diminishes the observed antimicrobial and cytotoxic properties of the 2-(2'-pyridyl)- and 2-(2'-aminophenyl)-7-aminoquinoline-5,8-diones. A direct comparison of the antimicrobial and cytotoxic properties of a complete set of streptonigrin and lavendamycin partial structures is detailed in efforts to define the role peripheral substituents play in potentiating the biological properties of the naturally occurring and synthetic agents bearing the 7-aminoquinoline-5,8-dione AB ring system and in efforts to define the minimum, potent pharmacophore of the naturally occurring antitumor antibiotics. The relationship of these observations to a chemical mechanism of cellular toxicity is discussed.
123 citations
TL;DR: A unique pharmacophore model was derived which accommodates all presently known ligands of the benzodiazepine receptor, identifies sensitivity to steric hindrance close to the δ1 zone, accounts for R andS differential affinities and distinguishes requirements for agonist versus non-agonist activity profiles.
Abstract: Applied to seven potent benzodiazepine-receptor ligands belonging to chemically different classes, the active analog approach allowed the stepwise identification of the pharmacophoric pattern associated with the recognition by the benzodiazepine receptor. A unique pharmacophore model was derived which involves six critical zones: (a) a pi-electron rich aromatic (PAR) zone; (b) two electron-rich zones delta 1 and delta 2 placed at 5.0 and 4.5 A respectively from the reference centroid in the PAR zone; (c) a freely rotating aromatic ring (FRA) region; (d) an out-of-plane region (OPR), strongly associated with agonist properties; and (e) an additional hydrophobic region (AHR). The model accommodates all presently known ligands of the benzodiazepine receptor, identifies sensitivity to steric hindrance close to the delta 1 zone, accounts for R and S differential affinities and distinguishes requirements for agonist versus non-agonist activity profiles.
63 citations
TL;DR: A series of apomorphine congeners has been studied with respect to their ability to mimic the structural requirements of the dopamine pharmacophore in the potent and stereoselective dopamine receptor agonist (R)-apomorphine.
Abstract: A series of apomorphine congeners has been studied with respect to their ability to mimic the structural requirements of the dopamine pharmacophore in the potent and stereoselective dopamine receptor agonist (R)-apomorphine. Conformational energies of the mimicking structures calculated by molecular mechanics (MMP2) correlate well with the observed biological activities.
22 citations
TL;DR: An approach by which novel ligands can be designed for a receptor if a pharmacophore geometry has been established and the receptor-bound conformations of other ligands are known is introduced.
Abstract: We introduce an approach by which novel ligands can be designed for a receptor if a pharmacophore geometry has been established and the receptor-bound conformations of other ligands are known. We use the shape-matching method of Kuntz et al. [J. Mol. Biol., 161 (1982) 269–288] to search a database of molecular shapes for those molecules which can fit inside the combined volume of the known ligands and which have interatomic distances compatible with the pharmacophore geometry. Some of these molecules are then modified by interactive modeling techniques to better match the chemical properties of the known ligands. Our shape database (about 5000 candidate molecules) is derived from a subset of the Cambridge Crystallographic Database [Allen et al., Acta Crystallogr., Sect. B,35 (1979) 2331–2339]. We show, as an example, how several novel designs for nicotinic agonists can be derived by this approach, given a pharmacophore model derived from known agonists [Sheridan et al., J. Med. Chem., 29 (1986) 889–906]. This report complements our previous report [DesJarlais et al., J. Med. Chem., in press], which introduced a similar method for designing ligands when the structure of the receptor is known.
22 citations
TL;DR: The data suggest that further increases in spanner length and lipophilicity and optical resolution may improve the potential of a labeled bivalent beta 1-adrenoceptor antagonist to function as a myocardial imaging agent.
Abstract: Two series of bivalent ligands (P-X-P) containing the (R,S)-3-[(4-aminoaryl)oxy]-1-(isopropylamino)propan-2-ol pharmacophore and a connecting alpha,omega-dicarbonylpoly(methylene) [X = -OC(CH2)nCO-] or alpha,omega-N,N'-bis(carbonylmethylene) polymethylenediamine [X = -OCCH2NH(CH2)nNHCH2CO-] spanner were synthesized and evaluated for beta-adrenoceptor antagonist activity in rat heart and lung membrane preparations. The target compounds were obtained as a mixture of stereoisomers in modest yields by using a three to four step sequence beginning with N-benzylpractolol. The results from the competitive binding studies indicated that binding affinity increased by a factor of up to 160 by increasing the length of the group spanning the pharmacophore moieties. Modest increases in cardioselectivity were also obtained. The data suggest that further increases in spanner length and lipophilicity and optical resolution may improve the potential of a labeled bivalent beta 1-adrenoceptor antagonist to function as a myocardial imaging agent.
21 citations
TL;DR: The N-methyl derivative of the 4-(4-chloro-3-hydroxyphenyl) isomer, and the N- methyl group enhanced potency about twofold and the "pharmacophore" for selective dopamine D-1 antagonist activity appears to be a tertiary 2-phenethylamine.
Abstract: The isomeric 4-(3-chloro-4-hydroxyphenyl)- and 4-(4-chloro-3-hydroxyphenyl)-1,2,3,4-tetrahydroisoquinolines, the N-methyl derivative of the 4-(4-chloro-3-hydroxyphenyl) isomer, and 4-(3-hydroxyphenyl)-1,2,3,4-tetrahydroisoquinoline were synthesized and evaluated for dopamine D-1 antagonist activity. The 4-(3-chloro-4-hydroxyphenyl) and the 4-(3-hydroxyphenyl) isomer possessed similar potencies as D-1 antagonists. Introduction of the N-methyl group enhanced potency about twofold. The "pharmacophore" for selective dopamine D-1 antagonist activity appears to be a tertiary 2-(3-hydroxyphenyl)-2-phenethylamine.
18 citations
TL;DR: The chapter discusses molecular modeling studies of bioactive conformations of drugs; of 3D pharmacophore patterns; of inhibitor design, particularly when a 3D enzyme structure is available; of receptor mapping; and, finally, of protein and genetic engineering.
Abstract: Publisher Summary This chapter discusses significant recent applications of this methodology and some promising new developments. Recent bibliographies of molecular graphics and of theoretical calculations in molecular pharmacology contain more complete sets of references relevant to drug design and discovery. The chapter discusses molecular modeling studies of bioactive conformations of drugs; of 3D pharmacophore patterns, particularly for receptor agonists and antagonists; of inhibitor design, particularly when a 3D enzyme structure is available; of receptor mapping; and, finally, of protein and genetic engineering. The computational aids to drug design surveyed here are growing in sophistication, in relevance to “real-world” medicinal chemical research problems and in dissemination into the working pharmaceutical research environment. A number of enzyme and other macromolecular structures are becoming available from X-ray crystallography. Logically, these structures continue to be exploited in design of potential enzyme inhibitors. A systematic computational method for “screening” rigid ligands (taken from a data base of 3D structures) for complementarity of shape to an enzyme active site has been developed, as well as a method for allowing partial conformational flexibility in the “docking” process. Major current and future trends include reduction of hardware and software cost for using these methods, increased ease of use, and integration of these programs with other computational chemistry applications, such as chemical and biological data handling.
17 citations
TL;DR: It appears likely that a hydrophilic substituent in a certain region of the analgesic pharmacophore may also interact with the receptor as a secondary binding group and be presented in a precise three-dimensional arrangement.
Abstract: Extensive conformational calculations were performed on the potent opiate analgesics etorphine, PET, R30490 and etonitazene to determine all of their many low-energy conformations. The results were used to characterize four possible models for binding of a simple pharmacophore, comprising two phenyl rings plus a protonated nitrogen, to opiate analgesic receptors. These four models may define the necessary three-dimensional features leading to particular opiate actions. The model favoured for μ receptor activity can accommodate a protonated nitrogen, an aromatic ring (which may be substituted with an electronegative group) and a second lipophilic group. These structural features must be presented in a precise three-dimensional arrangement. It appears likely that a hydrophilic substituent in a certain region of the analgesic pharmacophore may also interact with the receptor as a secondary binding group.
15 citations
TL;DR: The regression analysis of log KD with respect to the distances of the vectors of the acidic hydrogen support the hypothesis that these compounds bind to the receptor as donors in hydrogen bond formation.
Abstract: Using computer-aided molecular modeling techniques to analyze models recently proposed for the receptor binding sites of dopaminergic agonists, we superimposed the chemical structures of various compounds that mimic the pharmacological behavior of dopamine, as well as inactive enantiomers, on a postulated three-dimensional frame of reference. We analyzed the vector directionalities of the lone pairs of the nitrogen common to these molecules, and the acidic hydrogen of phenols (in aminoindanes, aminotetralins, apomorphines,p-phenol-piperazines, octahydrobenzo(g)quinolines, octahydrobenzo(f)quinolines, and benzazepines) or of nitrogen (in ergoline-type compounds and related structures). This model, when expressed as distances from that of the reference compound pergolide, correlates with the dopaminergic binding affinity observed in compounds previously reported to act on the dopaminergic system in the central nervous system (CNS). The regression analysis of log KD with respect to the distances of the vectors of the acidic hydrogen support the hypothesis that these compounds bind to the receptor as donors in hydrogen bond formation.
13 citations
TL;DR: The preparation of 7-amino-2-(2′-pyridyl)quinoline-5,8-quinone-6′-carboxylic acid constituting a potential minimum, potent pharmacophore of streptonigrin and lavendamycin, two structurally-related naturally-occurring antitumor-antibiotic, is detailed.
TL;DR: The pharmacophores, which describe the relative location in space of the unsaturated systems, the dimethyl groups and the ester moiety, may be useful in the design of novel compounds with pyrethroid activity.
Abstract: A molecular modelling and computer graphics study of a series of pyrethroid insecticides has been carried out. The three-dimensional arrangement of the groups essential for the biological activity (pharmacophore) has been identified for the acid and the alcohol moieties, respectively. These pharmacophores are based on the relationship between molecular structure and biological activity for a number of pyrethroid esters. The pharmacophores, which describe the relative location in space of the unsaturated systems, the dimethyl groups and the ester moiety, may be useful in the design of novel compounds with pyrethroid activity.
TL;DR: In this article, the spatial correspondence between apomorphine and ergoline was derived by matching their molecular electrostatic potential (MEP) patterns surrounding the aromatic moieties with respect to the coincident aliphatic N atoms.
Abstract: Spatial correspondence between apomorphine, a prototype dopaminergic (DA) drug, and ergoline and some of its (partial) analogues were derived by matching their molecular electrostatic potential (MEP) patterns surrounding the aromatic moieties with respect to the coincident aliphatic N atoms. The MEP patterns were calculated from ab initio wave functions of model molecules. The congruent superimpositions of the molecular frameworks obtained between apomorphine and DA active ergoline analogues might corroborate the hypothesis that they bind with the same receptor sites when activating certain subtypes of the DA receptor.