Me 3-methoxy-2-trifluoromethylacrylate, readily prepd. by Wittig reaction from Me 3,3,3-trifluoropyruvate, has been treated with a no. of aryl(or heteroaryl)hydrazines. Under mild base catalysis, the resulting 3-hydrazinoacrylates undergo consecutive hydrogen fluoride elimination and intramol. nucleophilic addn. to afford Me 1-(hetero)aryl-5-fluoropyrazole-4-carboxylates. 5-Aminopyrazoles have been obtained by direct reaction of Me 5-fluoro-1-phenylpyrazole-4-carboxylate with lithium amides, whereas 5-fluoro-1-phenylpyrazole-4-carboxamides have been formed by condensation of 5-fluoro-1-phenylpyrazole-4-carboxylic acid with amines. [on SciFinder (R)]
Titre
Fluorine-sacrificial cyclizations as an access to 5-fluoropyrazoles
Publié dans
European Journal of Organic Chemistry
Numéro
5
Pages
823-828
Date
2000
Note
CAN 132:308284 28-8 Heterocyclic Compounds (More Than One Hetero Atom) Section de Chimie (BCh),Universite of Lausanne,Lausanne,Switz. Journal 1434-193X written in English. 134-29-2; 142-04-1; 20265-97-8; 27191-09-9 Role: RCT (Reactant), RACT (Reactant or reagent) (amidation of fluorophenylpyrazolecarboxylic acid by); 100-63-0; 2368-80-1; 4930-98-7; 5329-12-4; 10449-07-7; 13089-11-7; 33670-32-5 Role: RCT (Reactant), RACT (Reactant or reagent) (fluorine-sacrificial cyclizations as access to 5-fluoropyrazoles); 265986-40-1P; 265986-41-2P; 265986-42-3P; 265986-43-4P; 265986-44-5P; 265986-46-7P; 265986-47-8P; 265986-48-9P; 265986-49-0P; 265986-50-3P; 265986-57-0P; 265986-62-7P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (fluorine-sacrificial cyclizations as access to 5-fluoropyrazoles); 529-37-3P (4(1H)-Quinolinone); 195988-50-2P; 265986-45-6P; 265986-51-4P; 265986-52-5P; 265986-53-6P; 265986-54-7P; 265986-55-8P; 265986-56-9P; 265986-58-1P; 265986-59-2P; 265986-60-5P; 265986-61-6P Role: SPN (Synthetic preparation), PREP (Preparation) (fluorine-sacrificial cyclizations as access to 5-fluoropyrazoles); 62-53-3 (Benzenamine); 95-54-5 (1,2-Benzenediamine); 100-61-8 Role: RCT (Reactant), RACT (Reactant or reagent) (reaction with Me methoxy(trifluoromethyl)acrylate)
Date de création de la notice
2006-03-03
