Síntese e caracterização de novos compostos mesoiônicos e derivados dos sistemas 1,3-tiazólio-5-tiolato e 1,3-diazólio-5-tiolato

• Ano de defesa: 2012
• Autor(a) principal: Figueirôa, Juliana Andreza
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraí­ba; BR; Química; Programa de Pós-Graduação em Química; UFPB
• Palavras-chave em Português: Compostos mesoiônicos; Reações de cicloadição/reversão 1,3-dipolar; Técnicas espectroscópias; Mesoionic Compounds; Cycloaddition Reactions / Cycloreversion 1,3-dipolar; Spectroscopic techniques; CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/tede/7063

Mesoionic compounds are notable heterocyclic for having the most diverse biological properties, physical and chemical properties. Are defined as flat and non-aromatic heterocyclic Betaines stabilized by electron delocalization. Through an in situ cycloaddition/cicloreversion 1,3-dipolar were obtained two mesoionic, MI-1.1 and MI-1.2 through of the interconversion system 1,3-oxazólio-5-olato (Munchnonas) for 1,3-tiazólio-5-tiolato. A nucleophilic substitution reaction with excess methyl iodide, CH3I, promoted the first modification to the mesoionic system were changed of free base to iodates salts, S-methylated forming derivatives mesoionic, MI-2.1 e MI-2.2. These underwent a cyclodehydration reaction in the presence of acetic anhydride yielding two mesoionic system 1,3-diazolium-5-thiolate, MI-3.1 and MI-3.2, which in turn were alkylated again and originated two derived in the form of iodates salts S-methylated, MI-4.1 and MI-4.2. As the mesoionic and its derivatives: MI-2.1, MI-2.2, MI-3.1, MI-3.2, MI-4.1 and MI-4.2 and unpublished literature. Their structures were elucidated by spectroscopic techniques for RMN 1H and 13C and infrared light through a comparative analysis with existing structures.