title: Hydrogen-bond-mediated self-assembly of 26-membered diaza tetraester crowns of 3,5-disubstituted 1H-pyrazole. Dimerization study in the solid state and in CDCl3 solution.
abstract: By using an improved synthetic method reported earlier, the cyclic stannoxanes obtained from RN-diethanolamine (R = Me, Bu) and dibutyltin oxide have been reacted with 1H-pyrazole-3,5-dicarbonyl dichloride to afford 26-membered diaza tetraester crowns (1, R = Me; 3, R = Bu) and 39-membered triaza hexaester crowns (2, R = Me; 4, R = Bu). The new structures were identified from their analytical and spectroscopic ((1)H and (13)C NMR, FAB-MS, and/or ESI-MS) data. Both diaza tetraester crowns (1 and 3), containing two 1H-pyrazole units, self-assemble into dimeric species through the formation of four hydrogen bonds involving the two NH pyrazole groups and the two tertiary amine groups of both crowns, as proved by X-ray crystallography and NMR analysis. Preliminary NMR, ESI-MS, MALDI-TOF-MS, and molecular modeling studies suggest that, in CDCl(3) solution, 1 interacts with ethyleneurea (ETU), affording 1:1, 2:1, and 2:2 1-ETU complexes.
authors.affiliation: Instituto de Química Médica and Centro de Química Orgánica Lora-Tamayo CSIC, Juan de la Cierva 3, 28006 Madrid, Spain.
authors.forename: Felipe
authors.initials: F
authors.lastname: Reviriego
authors.forename: Pilar
authors.initials: P
authors.lastname: Navarro
authors.forename: Vicente J
authors.initials: VJ
authors.lastname: Arán
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Jimeno
authors.forename: Enrique
authors.initials: E
authors.lastname: García-España
authors.forename: Julio
authors.initials: J
authors.lastname: Latorre
authors.forename: Maria J R
authors.initials: MJ
authors.lastname: Yunta
mesh_terms: D000588:Amines / Q000737:chemistry; D002725:Chloroform / Q000737:chemistry; D047248:Crown Compounds / Q000032:analysis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003500:Cyclization; D003903:Deuterium / Q000737:chemistry; D019281:Dimerization; D004952:Esters / Q000032:analysis / Q000737:chemistry*; D004983:Ethanolamines / Q000737:chemistry; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015335:Molecular Probes / Q000032:analysis / Q000737:chemistry*; D009947:Organotin Compounds / Q000737:chemistry; D011720:Pyrazoles / Q000032:analysis / Q000737:chemistry*; D012996:Solutions; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000588:Amines; D047248:Crown Compounds; D004952:Esters; D004983:Ethanolamines; D015335:Molecular Probes; D009947:Organotin Compounds; D011720:Pyrazoles; D012996:Solutions; D002725:Chloroform; D003903:Deuterium; C020283:diethanolamine; C031078:dibutyltin oxide