Ring Contains N And P Only, Or May Include In Addition To The Required N And P, Only C, S, Or O (9/6581; 9/6584; 9/6584a) Patents (Class 987/34)

Ring contains at least two p atoms (9/6581d; 9/6587; 9/659; 9/6593) (Class 987/35)

There are no patents to show for this class.