A new tricyclic ring and a nitrogen-sulfur analogue of the tri-pentagon bowl. Substituted 5,6,7,7a-tetrahydropyrrolo[2,1-b]-1,3,4-thiadiazole- endo-6,7-dicarboxyimides.

The first examples of a bowl-shaped tricyclic nitrogen-sulfur analogue of the tri-pentagon bowl are reported; substituted 5,6,7,7a-tetrahydropyrrolo[2,1-b]-1,3,4-thiadiazole-endo-6,7-dicarboxyimides are synthesised by a relatively simple route.