Design, synthesis, X-ray analysis, and dopamine receptor-modulating activity of mimics of the "C5" hydrogen-bonded conformation in the peptidomimetic 2-oxo-3(R)-[(2(S)-pyrrolidinylcarbonyl)amino]-1- pyrrolidineacetamide.
3(R)-(7a(S)-Hexahydro-1-oxo-3,3-dimethyl-1H-pyrrolo[1,2-c]imidazol-2-yl) - oxo-1-pyrrolidine-acetamide (2) and 3(R)-[1-(2,5-dioxopyrrolidino[3,4-c]piperazino)]-2-oxo-1- pyrrolidineacetamide (3) were designed and prepared as mimics of the "C5" hydrogen-bonded structure found in the crystal structure of 2-oxo-3(R)-[(2(S)-pyrrolidinylcarbonyl)amino]-1- pyrrolidineacetamide (1). Both compounds effectively restrict the psi 1 torsional angle to very near the value found in the X-ray structure of 1 as seen in the X-ray crystallographic determination of 2 and methyl 3(R)-[1-(2,5-dioxopyrrolidino[3,4-c]piperazino)]-2-oxo-1- pyrrolidineacetate (11), a diketopiperazine intermediate in the synthesis of 3. These analogs were tested for their ability to enhance the binding of the dopamine D2 receptor agonist N-propylnorapomorphine (NPA) in the absence and presence of 5'-guanylylimidodiphosphate (Gpp(NH)p). Both compounds enhanced [3H]-NPA binding in a dose-dependent manner by increasing both the binding affinity of the agonist and the number of high-affinity sites available for binding. Both 2 and 3 also attenuated the Gpp(NH)p-induced conversion of D2 receptor high-affinity states to the low-affinity states.
Baures
P W
PW
Department of Medicinal Chemistry, University of Minnesota, Minneapolis 55455.
Ojala
W H
WH
Gleason
W B
WB
Mishra
R K
RK
Johnson
R L
RL
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D018360:Crystallography, X-Ray; D015195:Drug Design; D006860:Hydrogen Bonding; D066298:In Vitro Techniques; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D011760:Pyrrolidinones / Q000737:chemistry* / Q000494:pharmacology; D011954:Receptors, Dopamine / Q000187:drug effects*
D011760:Pyrrolidinones; D011954:Receptors, Dopamine; C067487:3-(N-prolylamine)-2-oxo-1-pyrrolidineacetamide