A convenient synthesis of 3-and 5-amino-1H-pyrazoles via 3(5)-amino-4-(ethylsulfinyl)-1H-pyrazole desulfinylation

作者：Lassagne Frederic^*; Snegaroff Katia; Roisnel Thierry; Nassar Ekhlass; Mongin Florence

来源：Heterocyclic Communications, 2011, 17(3-4): 139-145.

DOI：10.1515/HC.2011.026

• biological evaluation
• desulfinylation
• hydrazine
• pyrazole
• pyrazolo[1,5-a]pyrimidines
• sulfoxide

Syntheses of 5-amino-3-aryl- and 3-amino-5-aryl-1H-pyrazoles from beta-bromo-alpha-(ethylsulfanyl)cinnamonitrile are described. The beta-bromo-alpha-(ethylsulfanyl) cinnamonitriles were oxidized with H(2)O(2) to the corresponding beta-bromo-alpha-(ethylsulfinyl) cinnamonitriles. Subsequent treatment of the resulting sulfoxides with hydrazine hydrate or methylhydrazine followed by hydrochloric acid hydrolysis afforded 5-amino-3-aryl- and 3-amino-5-aryl-1H-pyrazoles, respectively, in good yields.

• 出版日期2011-9