Study of the reactivity and transformations of styrylchromones and related compounds

Funder

Organizational Unit

Publications

Epoxidation Studies do 2-Styrylchromones

Publication . Santos, Clementina M.M.; Silva, Artur; Cavaleiro, José

Chromones represent an important class of compounds due to their broad range of applications. Certain natural and synthetic hydroxyl derivatives have shown important pharmacological, biocidal and mainly antioxidant activities.1 We are interested in the design of new 2-styrylchromones analogues containing hydroxyl groups at the C-3 and Cα=Cβ systems because they could increase the antioxidation activity of these compounds.2 Our first approach is the preparation of epoxide systems and then we intend to open the epoxide ring to give the desired hydroxyl derivatives. We studied the epoxidation of 2-styrylchromones 1 with hydrogen peroxide and iodosylbenzene using N,N'-bis(3,5-di-tert-butylsalicylidine)- 1,2-cyclohexanediaminomanganese (III) chloride [salen Mn(III)] as catalyst. Different experimental conditions have been used in order to prepare epoxide compounds 2 in moderate yields. We report here the synthetic details and structural characterisation of the obtained epoxides.

2003Conference object

Open access

Synthesis of new xanthone derivatives

Publication . Santos, Clementina M.M.; Silva, Artur; Cavaleiro, José

Xanthones are a class of heterocyclic compounds widely distributed in the plant kingdom (1). Since a long time ago, compounds with the xanthone core are of great interest for chemists, biologists and pharmacologists due to their potencial biological properties. Certain natural and synthetic derivatives have shown important anti-fungal, anti-tumour, anti-inflammatory as well as antioxidant activities (1 ,2).

2005Conference object

Open access

Epoxidation of 2-Styrylchromone derivatives

Publication . Santos, Clementina M.M.; Silva, Artur; Cavaleiro, José; Patonay, Támas; Lévai, Albert

2-Styrylchromones constitute a small group of natural heterocyclic compounds with significant biological properties. Certain natural and synthetic hydroxyl derivatives have shown important pharmacological and mainly antioxidant activities [1 ,2]. We are interested in the design of new 2-styrylchromones analogues containing hydroxyl groups at C-3 and in the Ca=C~ systems because they could increase the antioxidation activity of these type of compounds [2]. Our first approach is the preparation of epoxy systems and then we will try to open the epoxy ring to give the desired hydroxyl derivatives. We studied the epoxidation of 2-styryl-chromones 1 with hydrogen peroxide and iodosylbenzene using [salen Mn(lll)] as catalyst, and the epoxy products 2 were obtained in moderate yields. Since the best results were obtained with iodosylbenzene, we applied oxidant to compounds 3 in order to prepare 4. In this communication, we will report the synthetic details and the structural characterisation of the epoxides 3 and 4.

2004Conference object

Open access

New Synthesis of 2,3-Diarylxanthones

Publication . Santos, Clementina M.M.; Silva, Artur; Cavaleiro, José

A new synthesis of novel 2,3-diarylxantones is described. This was accomplished by Aldol condensation of 3-bromo-2-methylchromone with benzaldehydes leading to the formation of 3-bromo-2-styrylchromones, followed by Heck reaction with styrenes.

2005Journal article

Open access

NMR in the epoxidation of (E,E)-Cinnamylideneacetophenones

Publication . Santos, Clementina M.M.; Silva, Artur; Cavaleiro, José

The epoxidation of cinnamylideneacetophenones have been already performed with hydrogen peroxide as an oxidant in Julia's method [1] and with dimethyldioxirane [2], however no studies were performed using salen Mn(III) complexes as catalysts.

2006Conference object

Open access