Polycarbonyl heterocycles. Part III. Synthesis of 2,3-furanodione derivatives by ring transformations of thiazolidine-4,5-dione derivatives

Pyrrolidinetrione Derivatives: Synthesis And Applications in Heterocyclic Chemistry

“…Several examples of novel rearrangements of pyrrolidinetrione in the presence of nucleophiles have been reported. [62][63][64] Pyrrolidinetrione derivatives 33 undergo Dimroth 61 skeletal rearrangements to form various heterocyclic compounds such as pyrroline-2,3-dione, 62 furane-2,3-dione, 63 quinoline, 60 as well as fused heterocyclic systems. 64…”

“…The presence of a thioxo group at position 2 in pyrrolidinetriones 33 allows the ring opening to stable open-chain intermediates, which, in a sequence of reactions, are converted to the appropriate heterocyclic systems. 63 Pyrrolidine-2-thioxo-4,5-dione derivatives 33, available from the corresponding thiazolidine-4,5-diones 32 (Scheme 10), underwent Dimroth rearrangement to furan-2,3-diones 65 in a one-pot procedure. 63 In the first step, treatment of 33 with an aliphatic amine led immediately to the formation of an orange-red salt.…”

“…63 Pyrrolidine-2-thioxo-4,5-dione derivatives 33, available from the corresponding thiazolidine-4,5-diones 32 (Scheme 10), underwent Dimroth rearrangement to furan-2,3-diones 65 in a one-pot procedure. 63 In the first step, treatment of 33 with an aliphatic amine led immediately to the formation of an orange-red salt. After addition of a strong nucleophile, such as sodium hydroxide, a nucleophilic attack at the C- An attractive feature of the described rearrangements from the synthetic point of view is the high yield of all compounds 65 formed.…”

“…64 Dimroth rearrangement of 5-dicyanomethylene thiazolidine-4-one derivatives 66 under morpholine treatment resulted in formation of deep-red complexes 67. 63 The dicyanomethylene substituent at C-4 in complexes 67 was used as nitrogen-containing component for the known cyclization to a pyridine ring. 68 Addition of sodium hydroxide to the deep red solution of 67 changed its color to light yellow.…”