6533b7d6fe1ef96bd1266fb7
RESEARCH PRODUCT
Radical Cyclization and 1,5-Hydrogen Transfer in Selected Aromatic Diazonium Salts
Giuseppe DaidoneBenedetta MaggioGianfranco FontanaDemetrio RaffaFrancesco Ferrantesubject
PharmacologyRadical-nucleophilic aromatic substitutionChemistryOrganic ChemistryOrganic chemistryHydrogen transferSettore CHIM/06 - Chimica OrganicaSettore CHIM/08 - Chimica FarmaceuticaRadical cyclizationRadical cyclizations. 15-hydrogen transfer. Diazonium salts. Isoxazole. Thiophene.Settore CHIM/02 - Chimica FisicaAnalytical Chemistrydescription
2-(Methyl(3-methyl-1-phenyl-1H-pyrazol-5-yl)carbamoyl)thiophene-3-diazonium hydrogen sulfate 20, 2-(methyl(3-methyl-isoxazol-5yl)carbamoyl)-benzenediazonium hydrogen sulfate 21 and 2-(methyl(phenyl)carbamoyl)-benzenediazonium hydrogen sulphate 22 were synthesized and reacted with a CuSO4/NaCl/ascorbic acid combination to give complex mixtures. The structures of the reaction products were elucidated, depending upon the pathways followed. Compound 20 almost exclusively afforded an Ar-5 cyclization product and trace amounts of the product derived from a competing Ar-6 Pschorr closure. In the case of compound 21, the Ar-6 cyclization was not observed, while the Ar-5 cyclization and 1,5-hydrogen radical transfer processes equally occurred. Finally, the Ar-6 cyclization was observed as the main process for compound 22, accompanied by the Ar-5 cyclization and, in a much lesser extent, by an 1,5-hydrogen radical transfer process.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2014-01-01 | HETEROCYCLES |