RESUMO
α-Isocyanoacetamide derivatives were first converted to oxazolines under newly developed conditions. These oxazolines were used as precursors of α-isocyanoacrylamides, which could lead to various 2-arylated imidazolones. In addition, it was shown that both oxazolines and their precursors could efficiently lead to imidazolones unsubstituted at C2 in a very rapid, one-pot transformation, thus paving the way toward unprecedented routes to imidazolones, having a good tolerance to different substitution patterns.
Assuntos
Aldeídos , Cianetos , ImidazóisRESUMO
Herein, palladium-catalyzed Miyaura borylation of 4-bromo-2,4'-bithiazoles followed by Suzuki-Miyaura cross-coupling reaction (named the MBSC process) with (hetero)aryl- and alkenyl halides is reported. This methodology offers rapid access to various 2',4-disubstituted 2,4'-bithiazole features including naturally-occurring 4-alkenylated and 4-pyridinylated 2,4'-bithiazoles. To prove its application, a concise approach for the synthesis of a heterocyclic cluster of the thiopeptide d-series antibiotic GE2270 is reported through a late-stage MBSC strategy.
Assuntos
Hidrocarbonetos Halogenados/química , Tiazóis/síntese química , Catálise , Técnicas de Química Sintética/métodos , Paládio/química , Peptídeos Cíclicos/química , Estereoisomerismo , Tiazóis/químicaRESUMO
A straightforward enantiomerically pure synthesis of the heterocyclic core of the D-series GE2270 is reported. The synthetic strategy combines the Hantzsch thiazole's building condensation with a cross-coupling reaction including direct C-H hetarylation to build and connect step-by-step thiazolyl moieties to the 5-bromopicolinate as readily available starting material.
RESUMO
The first one-pot synthesis of N-substituted 2-H-4-benzylidene imidazolones and their subsequent palladium-catalyzed and copper-assisted direct C2-H arylation and alkenylation with aryl- and alkenylhalides are described. This innovative synthesis is step-economical, azide-free, high yielding, highly flexible in the introduction of a variety of electronically different groups, and can be operated on large-scale. Moreover, the method allows direct access to C2-arylated or alkenylated imidazolone-based green fluorescent protein (GFP) and Kaede protein fluorophores, including ortho-hydroxylated models.
Assuntos
Compostos de Benzilideno/química , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/síntese química , Imidazóis/química , Catálise , Cobre/química , Estrutura Molecular , Paládio/químicaRESUMO
Direct C-H arylation and alkenylation of 4,4'-dialkylimidazolones with a broad range of halides under palladium and copper catalysis have been developed. This methodology is applied to the preparation of recently discovered fatty acid synthetase (FAS) inhibitors.
Assuntos
Alcenos/química , Hidrocarbonetos Aromáticos/química , Imidazóis/química , Paládio/química , Catálise , Inibidores Enzimáticos/química , Ácido Graxo Sintases/antagonistas & inibidores , Halogênios/química , HumanosRESUMO
A new series of push-pull arylvinyldiazines has been efficiently prepared by aldol condensation between the appropriate methyldiazine and aromatic aldehyde. The optical absorption and emission properties of these chromophores were studied in different solvents and media. These compounds act as polarity sensors with a strong positive emission solvatochromism. This behavior suggests a highly polar emitting state, which is characteristic of compounds that undergo an internal charge transfer upon excitation. These molecules also exhibit halochromic properties and are potential colorimetric and luminescence pH sensors. The second-order nonlinear properties have been investigated for some of the compounds, and large and positive µß are obtained, in particular, for pyrimidine derivatives.
Assuntos
Pirimidinas/química , Compostos de Vinila/química , Compostos de Vinila/síntese química , Absorção , Colorimetria , Luminescência , Fótons , Espectrofotometria UltravioletaRESUMO
The enantioselective BINOL-phosphate catalyzed formation of a quaternary carbon center, bearing a N-atom has been achieved through the self-coupling reaction of enamides; the corresponding products have been isolated in up to >99% ee and their application for the synthesis of versatile synthetic building blocks-beta-aminoketones-has been demonstrated.