Allosteric Modulators of the Adenosine A1 Receptor: Synthesis and Pharmacological Evaluation of 4-Substituted 2-Amino-3-benzoylthiophenes
摘要:
A series of 4-substituted 2-amino-3-benzoylthiophenes was screened using a functional assay of A A(1)AR-mediated phosphorylation of ERK 1/2 in intact CHO cells to identify both potential agonistic effects as well the ability to allosterically modulate the activity of the orthosteric agonist, R-PIA. More detailed concentration-response experiments were subsequently performed on two compounds (9a and 9o) utilizing both the ERK 1/2 assay as well as a second assay of [S-35]GTP gamma S binding to activated G proteins.
Phosphine-Catalyzed Addition/Cycloaddition Domino Reactions of β′-Acetoxy Allenoate: Highly Stereoselective Access to 2-Oxabicyclo[3.3.1]nonane and Cyclopenta[a]pyrrolizine
摘要:
Two classes of phosphine-catalyzed addition/cycloaddition domino reactions of beta'-acetoxy allenoate 1 have been developed. The reaction of 1 with 2-acyl-3-methyl-acrylonitrile 2 readily occurs to give 2-oxabicyclo[3.3.1]nonane 3, furnishing the beta'-addition/[4 + 4] cycloaddition domino sequence. In this sequence, beta'C of allenoate 1 is an electrophilic center, and its beta'C and gamma C serve as a 1,4-dipole. When the other reaction partner is switched to 2-acyl-3-(2-pyrrole)-acrylonitrile 8, a gamma-addition/[3 + 2] cycloaddition domino reaction is instead observed, in which allenoate 1 exhibits dual electrophilic reactivity of gamma C and 1,3-dipole chemical behavior of beta C and beta'C. Furthermore, both of these two asymmetric variants have also been achieved with up to 93% ee. The domino reactions presented in this report are valuable for highly stereoselective construction of complex structures under mild reaction conditions.
The chiral phosphine-triggered electrophilic ylide intermediate for a Morita–Baylis–Hillman carbonates activation strategy provides a promising method for the design of organocatalytic intermolecular higher-order annulation processes.