Autor(es): Carvalho, Mário Geraldo de ; Silva, Virginia C. da ; Silva, Tânia Maria Sarmento da ; Camara, Celso de Amorim ; Braz Filho, Raimundo ; Carvalho, Mário Geraldo de ; Silva, Virginia C. da ; Silva, Tânia Maria Sarmento da ; Camara, Celso de Amorim ; Braz Filho, Raimundo
Data: 2012
Origem: Oasisbr
Assunto(s): Flavonol; Isoflavone; Iodoflavonoid; Iodoisoflavonoid; Iodine derivatives
p. 21-28
Submitted by JURANDI DE SOUZA SILVA (jssufba@hotmail.com) on 2012-05-09T19:07:15Z No. of bitstreams: 1 __www.scielo.br_pdf_aabc_v81n1_a04v81n1.pdf: 513054 bytes, checksum: 2ead27a2ef8d9efea022eef1d090f71c (MD5)
Made available in DSpace on 2012-05-09T19:07:15Z (GMT). No. of bitstreams: 1 __www.scielo.br_pdf_aabc_v81n1_a04v81n1.pdf: 513054 bytes, checksum: 2ead27a2ef8d9efea022eef1d090f71c (MD5) Previous issue date: 2009
The reaction of the flavonol 3,7,3', 4'-tetra-O-methylquercetin (1) and of the isoflavone 7,4'-di-O-methylgenistein (2) with alkaline iodine in methanol afforded four new iodine derivatives: 8-iodo-5-hydroxy-3,7,3', 4'-tetramethoxy- flavone (1a) and 6-iodo-5-hydroxy-3,7,3', 4'-tetramethoxyflavone (1b) from 1; 2 afforded a mixture of two compounds, identified as a racemic mixture of (±)-trans-5-hydroxy-2,3,7,4'-tetramethoxy-8-iodo-isoflavanone (2a) and (±)-trans-5-hydroxy-2,3,7,4'-tetramethoxy-6,8-diiodo-isoflavanone (2b). The formation of these different products reveals a significant difference involving the chemical interaction between the reactive site of α, β-unsaturated ketones of flavonol and isoflavone under the tested reaction conditions (using I2/KOH/MeOH). Furthermore, the trans stereo selectivity is noteworthy in the nucleophylic addition of methanol at the isoflavone α, β-unsaturated system. The structures were identified on the basis of spectral data, mainly 1D and 2D NMR and mass spectra.
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