[Thieno(2',3':3,4)pyrazolo(1,5-a)pyrimidines and -triazines: synthesis of a novel ring system]

The novel tricyclic ring systems 14 can be prepared by reaction of thienopyrazoles 5 with 1,3-dielectrophiles, such as acetylacetone, dibenzoylmethane or 1,2,4-dithiazole 8. An other synthetic route for the preparation of the tricyclic systems, based on the pyrazoloazines 13, was investigated. The compounds 5 and 14 were tested for antiulcer activity.