19263-38-8Relevant academic research and scientific papers
Radical cyclization and 1,5-hydrogen transfer in selected aromatic diazonium salts
Maggio, Benedetta,Fontana, Gianfranco,Raffa, Demetrio,Ferrante, Francesco,Daidone, Giuseppe
, p. 83 - 101 (2014/02/14)
2-(Methyl-(3-methyl-1-phenyl-1H-pyrazol-5-yl)carbamoyl)thiophene- 3-diazonium hydrogen sulfate 20, 2-(methyl-(3-methylisoxazol-5-yl)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.
