Improved methodologies for synthesis of prenylated xanthones by microwave irradiation and combination of heterogeneous catalysis (K10 clay) with microwave irradiation

• Tipo: Artigo em Revista Científica Internacional
• Data: 2009

Autores

Raquel A P Castanheiro (Autor) Outra; Madalena M M Pinto (Autor) FFUP; Sara M M Cravo (Autor) FFUP; Diana C G A Pinto (Autor) Outra; Artur M S Silva (Autor) Outra; Anake Kijjoa (Autor) ICBAS

Revista

Título: Tetrahedron

Vol. 65 Nº 19

Páginas: 3848-3857

ISSN: 0040-4020

Editora: Elsevier

Indexação

ISI Web of Knowledge - 25 Citações

Scopus - 29 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-003-K4B

DOI: 10.1016/j.tet.2009.03.019

Abstract (EN): Eleven prenylated xanthone derivatives (4-9, 11-15) have been synthesized for the first time by the microwave irradiation method. Prenylation of the xanthone building blocks 1 and 2 with prenyl bromide in alkaline medium. using microwave irradiation, gave the oxyprenylated xanthones 4 and 6, as major products in high yields, as well as diprenylated by-products (5, 7, 8, and 9) in very low yields. Microwave irradiation of oxyprenylated xanthones 4 and 6 furnished three new Claisen rearranged products (11, 14, and 15), as well as the previously described dihydrofuranoxanthones (12, 13). Furthermore, three new (19, 20, 21) and three previously described (16,17,18) dihydropyranoxanthones have also been prepared by a one-pot synthesis from xanthones 1, 2, and 3, using Montmorillonite 100 clay as a heterogeneous catalyst and a combination of Montmorillonite K10 clay with microwave irradiation in various conditions. The presence of solvent and the type of the clay (commercial or city) were found to have a strong influence on the product yields. This is the first report of using these methodologies for the synthesis of dihydropyranoxanthone derivatives. The structures of the prenylated xanthones obtained were established by IR, UV, HRMS, and NMR ((1)H, (13)C, HSQC, and HMBC techniques.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 10