RESUMO
Monocyclic [11]annulenium cations, which are experimentally unknown, have been studied primarily via DFT methods but also with some CCSD(T) validation. We have located six minima: two doubly trans (26, 27), one triply trans (28), one singly trans (29), one quintuply trans (trannulene-type, 33), and one all-cis (31). The first three are aromatic, 33 is modestly aromatic, 29 is nonaromatic, and the last is a Möbius antiaromatic species. We also investigated the fusion of various numbers of three-membered rings (3MRs) to the central 11-membered ring (11MR). We found several planar, all-cis-[11]annulenium ion derivatives as well as another Möbius antiaromatic species (52b); for comparison, we also found planar, antiaromatic all-cis-[12]annulene (60) and [15]annulenium cation (61) derivatives. The (anti)aromatic characterization of these compounds is based mainly on calculated magnetic data for the ground singlet and vertical triplet states, although aromatic stabilization energies (ASE) are also considered. Data for optimized triplets, several of which are Möbius aromatic systems (31t, 52t, 63t, 64t), are also included. Several of these cations are reasonable synthetic targets.
RESUMO
Starting from fused barbaralanes, we come (theoretically) to a new class of delocalized molecules in which two polyenyl radical chains interact with each other through space in a bonding way, but do not form full sigma-bonds. These molecules resemble sigma-homologues of polyacenes and are bishomoaromatic.
RESUMO
Efficient routes to three classes of 10-membered oxa-enediynes are presented. The electronic and stereoelectronic contributions to half-lives are supported by density functional theory calculations. One member of this class cyclizes to give an isochroman which binds to and degrades the aryl hydrocarbon receptor (AhR).
Assuntos
Hidrocarbonetos Aromáticos/síntese química , Receptores de Hidrocarboneto Arílico/metabolismo , Alcinos/síntese química , Alcinos/química , Alcinos/farmacocinética , Animais , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Compostos Heterocíclicos com 1 Anel/síntese química , Compostos Heterocíclicos com 1 Anel/química , Compostos Heterocíclicos com 1 Anel/farmacocinética , Hidrocarbonetos Aromáticos/química , Hidrocarbonetos Aromáticos/farmacocinética , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
A series of halogen-substituted cyclic enediynes were prepared with use of carbenoid coupling strategy. DFT analysis, initially used to identify synthesis candidates, was also employed to rationalize the propensity for cycloaromatization of the compounds. In all cases studied the halogen atom had a strongly retardative effect on the thermal Bergman cycloaromatization reaction. The isolation of the first C-9 monochloroenediyne is noteworthy, and may find application in prodrug design.
Assuntos
Química Orgânica/métodos , Hidrocarbonetos Aromáticos/química , Hidrocarbonetos Halogenados/química , Compostos de Vinila/química , Alcinos/química , Catálise , Ciclização , Hidrocarbonetos Aromáticos/síntese química , Hidrocarbonetos Halogenados/síntese química , Conformação Molecular , Estrutura Molecular , TermodinâmicaRESUMO
A series of aryl amines was found to induce cleavage of DNA. Subsequent refinement led to an efficient family of dimeric derivatives capable of cleavage at low concentration. Initial investigations suggest this is an unprecedented mode of DNA cleavage, which may be ultimately applied to the development of sequence-specific agents.
