Pulmonary-Allergy, Dermatological, Gastrointestinal & Arthritis: Benzopyran and benzothiopyran derivatives as PAF antagonists

Abstract

A series of novel benzopyran- and benzothiopyrancontaining compounds with platelet activating factor (PAF) antagonist activity are disclosed. Thirty-one compounds are exemplified, with full preparative details given. Three of these examples (including 1 and 2) were characterised as PAF antagonists in vitro by their ability to inhibit PAF-induced platelet aggregation (IC₅₀ values of 3–10 μM), and in vivo by their ability to block PAF-saduced bronchoconstriction in anaesthetised guinea-pigs (ED₅₀ values of 3–10 μg/kg).