Síntese de 4,5-bis(trifluormetil)-1h-pirazóis através de reações eletrofílicas e nucleofílicas empregando NIS e MFSDA

Detalhes bibliográficos
Ano de defesa: 2019
Autor(a) principal: Junges, Andrizia de Freitas
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Santa Maria
Brasil
Química
UFSM
Programa de Pós-Graduação em Química
Centro de Ciências Naturais e Exatas
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
NIS
Link de acesso: http://repositorio.ufsm.br/handle/1/16761
Resumo: This dissertation describes the development of an efficient methodology for the functionalization of position 4 of 3-alkyl(aryl)-1-aryl-5-trifluoromethyl-1H-pyrazoles systems by halogenation and subsequent reaction with trifluoromethylating reagent MFSDA, thus obtaining a series of six unpublished examples of 4-iodo-5-trifluoromethyl-1H -pyrazoles in addition to seven unpublished compounds of the 4,5- bis(trifluoromethyl)-1H-pyrazoles series. Initially eight examples of 1-aryl-3-alkyl (aryl) -5-trifluoromethyl-1H-pyrazoles where aryl = C6H5, 4-FC6H4, 4-ClC6H4 and alkyl = Me, c-Pr, i-Pr, n-Bu from the cyclocondensation reaction [3 + 2] between 4-alkyl (aryl) -4-alkoxy-1,1,1-trifluoro-3-alken-2-ones and arylhydrazines in yields of 91-94%. The synthesized starting materials were then subjected to CF3COOH -catalyzed electrophilic iodination using the N-iodosuccinimide (NIS) reagent resulting in a series of 4-iodo-5-trifluoromethyl-1H-pyrazoles in yields of 75-87%. Subsequently the optimization of the methodology of insertion of trifluoromethyl at the 4-position of the series of 4-iodo-5-trifluoromethyl-1H-pyrazoles through nucleophilic substitution using the MFSDA reagent was performed. For this, different copper salts and additives were tested, besides the study of the reaction in argon atmosphere. By optimizing the methodology it was possible to synthesize an unpublished series of 4,5-bis(trifluoromethyl)-1H-pyrazoles in yields of up to 79%.