Encontrados 5 documentos, a visualizar página 1 de 1

New syntheses of novel arylxanthones

Xanthones represent an outstanding class of oxyg~1_1ated heterocycles widespread in nature, commonly distributed in several higher plant families, such as Gentianaceae, Guttiferae and Polygalaceae and in a few families of fungi and lichens [1]. Both natural and synthetic derivatives often endowed with interesting pharmacological properties (e.g. anti-inflammatory, antitumour and antioxidant activities [1,2]. Na...

Structure determination of some oxygen and nitrogen heterocyclic compounds by NMR

Oxygen heterocyclic compounds are widely distributed in Nature, being chromone and xanthone derivatives some examples. For instance, the xanthone ring system is a structural motif prevalent in higher plants such as those of Guttiferae and Gentianaceae families.1 Both natural and synthetic derivatives often endowed with interesting pharmacological properties, such as anti-inflammatory,2 antitumour3 and antioxida...

Synthesis of Novel 1-Aryl-9H-xanthen-9-ones

A novel route for the synthesis of 1-aryl-9H-xanthen-9-ones is reported. This methodology involves the condensation of 2-methylchromone with cinammaldehydes leading to (E,E)-2-(4-arylbuta-1,3-dien-1-yl)-4H-chromen-4-ones. The final step was the electrocyclization and oxidation reactions of the latter compounds, in an one-pot synthesis, giving the desired 1-aryl-9H-xanthen-9-ones.

Novas rotas de síntese de 1-arilxantonas

O trabalho descrito nesta dissertação envolve num primeiro passo a síntese de (E,E)-2-(4-arilbuta-1,3-dien-1-il)-3-bromo-4H-cromen-4-onas e (E,E)-2-(4-arilbuta-1,3-dien-1-il)-4H-cromen-4-onas através de uma reacção de condensação de 3-bromo-2-metil-4H-cromen-4-ona e 2-metil-4H-cromen-4-ona com cinamaldeídos convenientemente substituídos. As cromonas foram obtidas com rendimentos moderados a bons. As (E,E)-2-(4-...

Recent developments in the synthesis of 1-aryl-9H-xanthen-9-ones