RESUMEN
Novel conditions for the transformation of gem-dibromomethylenes to ketones are described. gem-Dibromo compounds were treated with acetic anhydride and triethylamine in dichloromethane/water at room temperature under an air atmosphere to give the corresponding ketones in moderate yields. A radical mechanism is proposed based on experimental results.
Asunto(s)
Cetonas/química , Compuestos Organometálicos/química , Acetilación , Estructura MolecularRESUMEN
We describe here the synthesis of [(14)C]-2-(3-chlorophenyloxy)-3-[3-(3-hydroxy)pyridin-4-yl propoxy]pyridine (1), a phosphodiesterase 4 inhibitor. [(14)C]-Labeled 1 was prepared in three steps from [(14)C]-2-bromopyridin-3-ol in an overall yield of 32%. Preparation of [(14)C]-labeled 2 and 3, two metabolites of 1, is also described.
Asunto(s)
Inhibidores de Fosfodiesterasa 4/síntesis química , Piridinas/síntesis química , Radiofármacos/síntesis química , Radioisótopos de Carbono/química , Piridinas/químicaRESUMEN
The stereocontrolled synthesis of a racemic carboxylic acid of crambescin B, a marine alkaloid, is described. The synthesis features two highly stereoselective reactions: (I) palladium-catalyzed hydroxymethylation of an alkynyl aziridine having an N-guanidino group and (II) cascade bromocyclization providing a spiro-hemiaminal structure. The cell-based colorimetric assay showed that the synthesized carboxylic acid exhibited a potent inhibitory activity on voltage-gated sodium channels.
Asunto(s)
Ácidos Carboxílicos/farmacología , Pirimidinas/farmacología , Compuestos de Espiro/farmacología , Canales de Sodio Activados por Voltaje/metabolismo , Ácidos Carboxílicos/síntesis química , Ácidos Carboxílicos/química , Colorimetría , Conformación Molecular , Pirimidinas/síntesis química , Pirimidinas/química , Compuestos de Espiro/síntesis química , Compuestos de Espiro/química , EstereoisomerismoRESUMEN
Two terphenyl quinones were synthesized for a structural study on a naturally occurring biologically active terphenyl quinone. 3-Methoxy-5,6-diphenylcyclohexa-3,5-dien-1,2-dione, a possible structure proposed by our analysis of the NMR spectra, was synthesized by Suzuki-Miyaura coupling and subsequent oxidation of the resulting substituted phenol, although not being identical to the natural product. Recently isolated 3-methoxy-2,5-diphenylcyclohexa-2,5-dien-1,4-dione was synthesized from a commercially available 2,5-diphenyl-1,4-benzoquinone in three steps in a good overall yield, and its NMR spectra were identical to those of the natural product.
Asunto(s)
Benzoquinonas/química , Productos Biológicos/química , Compuestos de Terfenilo/química , Espectroscopía de Resonancia MagnéticaRESUMEN
Naturally occurring terphenyls and related compounds such as terferol and its corresponding quinone and phlebiarubrone were synthesized from 2,5-diphenyl-1,4-benzoquinone. According to the proposed biosynthetic pathway, chemical conversion of phlebiarubrone to ustalic acid, a toxic compound isolated from the poisonous mushroom, Tricholoma ustale, was examined to find a low-yield conversion to the ustalic acid dimethyl ester.
