Three-component spiro-heterocyclization of 4,5-diphenyl-1H-pyrrole-2,3-dione under the action of malononitrile and 3-hydroxycyclohex-2-en-1-ones

An Isoxazole Strategy for Molybdenum-Mediated Synthesis of 5-Mono- and 4,5-Disubstituted 1H-Pyrrole-2,3-diones

“…1a−d,2−4 On the contrary, reactions of other monocyclic 1H-pyrrole-2,3-diones, proceeding with preservation of pyrrole moiety, have hardly been studied. Thus, only 4,5-diphenyl-1H-pyrrole-2,3-dione was used in spiro-heterocyclizations 5 and only the Diels−Alder reaction of butadiene with 5-phenyl-1H-pyrrole-2,3-dione was published. 2a This state of affairs is mainly due to the availability of common and convenient methods for the preparation of 4alkoxycarbonyl/benzoyl-5-aryl-1H-pyrrole-2,3-diones, based on the reaction of oxalyl chloride with readily available enamines (alkyl 3-amino-3-arylprop-2-enoanes 6 and 3-amino-3-aryl-1-phenylprop-2-en-1-ones, 7 respectively), and to the absence of reliable approaches to the synthesis of pyrrole-2,3diones that lack electron-withdrawing substituents.…”

Three-component spiro heterocyclization of 1H-pyrrole-2,3-diones with malononitrile and pyrazolones. Crystal and molecular structure of a spiro[pyrano[2,3-c]-pyrazole-4,3′-pyrrole]

“…We previously showed that three-component reactions of 1H-pyrrole-2,3-diones with malononitrile and six-membered carbocyclic [1,2] and heterocyclic enols [3] involve initial condensation of the ketone carbonyl group (C 3 =O) of the pyrroledione with the methylene group of malononitrile, followed by nucleophilic addition of the β-CH and OH groups of the enol to the C 3 atom and cyano group. In order to extend the scope of this spiro heterocyclization in the present work we used as heterocyclic enols 1H-pyrazole-5(4H)-ones.…”