title: Mass spectrometry study of N-alkylbenzenesulfonamides with potential antagonist activity to potassium channels.
abstract: Herein, we report the synthesis and mass spectrometry studies of several N-alkylbenzenesulfonamides structurally related to sulfanilic acid. The compounds were synthesized using a modified Schotten-Baumann reaction coupled with Meisenheimer arylation. Sequential mass spectrometry by negative mode electrospray ionization (ESI(-)-MS/MS) showed the formation of sulfoxylate anion (m/z 65) observed in the mass spectrum of p-chloro-N-alkylbenzenesulfonamides. Investigation of the unexpected loss of two water molecules, as observed by electron ionization mass spectrometry (EI-MS) analysis of p-(N-alkyl)lactam sulfonamides, led to the proposal of corresponding fragmentation pathways. These compounds showed loss of neutral iminosulfane dioxide molecule (M-79) with formation of ions observed at m/z 344 and 377. These ions were formed by rearrangement on ESI(+)-MS/MS analysis. Some of the molecules showed antagonistic activity against Kv3.1 voltage-gated potassium channels.
authors.affiliation: Laboratório de Química Orgânica Fina, Departamento de Física, Química e Biologia, Faculdade de Ciências e Tecnologia, Universidade Estadual Paulista (UNESP), C.P. 467, Presidente Prudente, SP, 19060-900, Brazil.
authors.forename: Carina C
authors.initials: CC
authors.lastname: Martins
authors.affiliation: Laboratório de Química Orgânica Fina, Departamento de Física, Química e Biologia, Faculdade de Ciências e Tecnologia, Universidade Estadual Paulista (UNESP), C.P. 467, Presidente Prudente, SP, 19060-900, Brazil.
authors.forename: Carlos A Zanutto
authors.initials: CA
authors.lastname: Bassetto
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, UNICAMP, Campinas, SP, 13083‑970, Brazil.
authors.forename: Jandyson M
authors.initials: JM
authors.lastname: Santos
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, UNICAMP, Campinas, SP, 13083‑970, Brazil.
authors.forename: Marcos N
authors.initials: MN
authors.lastname: Eberlin
authors.affiliation: Departamento de Química Inorgânica, Instituto de Química, Universidade de Campinas, UNICAMP, Campinas, 13083-970, SP, Brazil.
authors.forename: Alvicler
authors.initials: A
authors.lastname: Magalhães
authors.affiliation: Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil.
authors.forename: Wamberto
authors.initials: W
authors.lastname: Varanda
authors.affiliation: Laboratório de Química Orgânica Fina, Departamento de Física, Química e Biologia, Faculdade de Ciências e Tecnologia, Universidade Estadual Paulista (UNESP), C.P. 467, Presidente Prudente, SP, 19060-900, Brazil. eperez@fct.unesp.br.
authors.forename: Eduardo R Perez
authors.initials: ER
authors.lastname: Gonzalez
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry*; D015195:Drug Design; D026902:Potassium Channel Blockers / Q000737:chemistry*; D051670:Shaw Potassium Channels / Q000187:drug effects*; D021241:Spectrometry, Mass, Electrospray Ionization; D013425:Sulfanilic Acids / Q000737:chemistry*; D013449:Sulfonamides / Q000138:chemical synthesis / Q000737:chemistry*; D053719:Tandem Mass Spectrometry
chemical_list: D000900:Anti-Bacterial Agents; D026902:Potassium Channel Blockers; D051670:Shaw Potassium Channels; D013425:Sulfanilic Acids; D013449:Sulfonamides
keywords: ESI-MS/MS; Kv3.1; Mass spectrometry; N-alkylbenzenesulfonamides