Synthesis and Biological Activity of Various Derivatives of a Novel Class of Potent, Selective, and Orally Active Prostaglandin D<sub>2</sub> Receptor Antagonists. 1. Bicyclo[2.2.1]heptane Derivatives
Novel prostaglandin D(2) (PGD(2)) receptor antagonists were synthesized as a potential new class of antiallergic agents having a bicyclo[2.2.1]heptane ring system with sulfonamide groups. Some of them exhibit extremely potent antagonism of the PGD(2) receptor in radioligand binding and cAMP formation assays with IC(50) values below 50 nM and much less antagonism of TXA(2) and PGI(2) receptors. These