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Synthesis of 5-chloropyrazoles by chlorodediazoniation with sulfur dioxide |
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| Authors: | Susumu Yamamoto Katsushi Morimoto Toshiaki Sato |
| Abstract: | A facile synthesis of 5 -chloropyrazoles 4a-e from 5 -aminopyrazoles 2a-e via diazotization followed by chlorodediazoniation is described. A new application of sulfur dioxide as a catalyst was demonstrated to be the best for the chlorodediazoniation of diazonium chlorides 3a-e . |
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