2H,5H-[1]benzothiopyrano [4,3-b]pyran derivatives with platelet antiaggregating activity.

The synthesis of some N,N-disubstituted 4-amino-3-phenyl-2H,5H-[1]benzothiopyrano [4,3-b]pyran-2-ones by reaction of phenylchloroketene with a series of N,N-disubstituted 3-aminomethylene-2,3-dihydro-4H-1-benzothiopyran-4-ones, followed by dehydrochlorination of the primary adducts with DBN, is described. Some of these compounds showed a strong platelet antiaggregating activity in vitro, superior to that of acetylsalicylic acid.