1-Arylimino-pyrazol-Betaine, Pyrazole und 1,2,4-Triazine aus 3-Arylazo-propens�ure-N-chloroamiden
摘要:
Reaction of 3-arylazo-propenoic acid amides 5 with NaOCl yields N-chloroamides 6 which give under alkaline conditions 1,2,4-triazines 9 and 10 (products of a Hofmann degradation). This reaction competes with an intramolecular electrophilic amination and a 1,2-shift reaction giving I-arylimino-pyrazole betaines 11 and 4-chloroimino-pyrazolones 13. Exchange of the halogen in 11 with nucleophiles leads to further betaines 12. Bis-pyrazole 14 and 1,2,3-triazoles 15 are available from 13b. The X-ray structure analysis of compound 11b is discussed.
Cu-Mediated Expeditious Annulation of Alkyl 3-Aminoacrylates with Aryldiazonium Salts: Access to Alkyl <i>N</i><sup>2</sup>-Aryl 1,2,3-Triazole-carboxylates for Druglike Molecular Synthesis
作者:Hao-Nan Liu、Hao-Qiang Cao、Chi Wai Cheung、Jun-An Ma
DOI:10.1021/acs.orglett.0c00006
日期:2020.2.21
Alkyl N-aryl 1,2,3-triazole-carboxylates are important molecules or intermediates in medicinal chemistry, but the synthesis of N2-aryl counterparts remains elusive. Herein, we describe a Cu-mediated annulation reaction of alkyl 3-aminoacrylates with aryldiazonium salts, both of which are readily available substrates. Furthermore, alkyl 2-aminoacrylates are also viable substrates. Diverse alkyl N2-aryl