Analogues of doxanthrine reveal differences between the dopamine D1 receptor binding properties of chromanoisoquinolines and hexahydrobenzo[a]phenanthridines.
Efforts to develop selective agonists for dopamine D(1)-like receptors led to the discovery of dihydrexidine and doxanthrine, two bioisosteric β-phenyldopamine-type full agonist ligands that display selectivity and potency at D(1)-like receptors. We report herein an improved methodology for the synthesis of substituted chromanoisoquinolines (doxanthrine derivatives) and the evaluation of several new compounds for their ability to bind to D(1)- and D(2)-like receptors. Identical pendant phenyl ring substitutions on the dihydrexidine and doxanthrine templates surprisingly led to different effects on D(1)-like receptor binding, suggesting important differences between the interactions of these ligands with the D(1) receptor. We propose, based on the biological results and molecular modeling studies, that slight conformational differences between the tetralin and chroman-based compounds lead to a shift in the location of the pendant ring substituents within the receptor.
Quimique Cía. Ltda., P.O. Box 17-07-9009, Quito, Ecuador. jpcueva@quimique.com
Juan Pablo
JP
Cueva
Benjamin R
BR
Chemel
Jose I
JI
Juncosa
Markus A
MA
Lill
Val J
VJ
Watts
David E
DE
Nichols
D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D018491:Dopamine Agonists / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007546:Isoquinolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D010617:Phenanthridines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013552:Swine
C516224:2,3-dihydroxy-6a,7,8,12b-tetrahydro-6H-chromeno(3,4-c)isoquinoline; D018491:Dopamine Agonists; D007546:Isoquinolines; D010617:Phenanthridines; D017447:Receptors, Dopamine D1