Solid-state ¹³C NMR and molecular modeling studies of acetyl aleuritolic acid obtained from Croton cajucara

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• 作者：Rosane Aguiar da Silva San Gil ; Magaly Girã ; o Albuquerque ; Ricardo Bicca de Alencastro ; Angelo da Cunha Pinto ; Fabiano do Espí ; rito Santo Gomes ; Tereza Neuma de Castro Dantas ; Maria Aparecida
• 关键词：Solid-state ¹³C NMR ; ¹³C NMR CP/MAS ; Acetyl aleuritolic acid ; Polymorphism ; Croton cajucara
• 刊名：Journal of Molecular Structure
• 出版年：2008
• 出版时间：14 August 2008
• 年：2008
• 卷：885
• 期：1-3
• 页码：82-88
• 全文大小：459 K

文摘

Solid-state ¹³C nuclear magnetic resonance (¹³C NMR) with magic-angle spinning (MAS) and with cross-polarization and magic-angle spinning (CP/MAS) spectra, and differential scanning calorimetry (DSC) techniques were used to obtain structural data from a sample of acetyl aleuritolic acid (AAA) extracted from the stem bark of Croton cajucara Benth. (Euphorbiaceae) and recrystallized from acetone. Since solid-state ¹³C NMR results suggested the presence of more than one molecule in the unitary cell for the AAA, DSC analysis and molecular modeling calculations were used to access this possibility. The absence of phase transition peaks in the DSC spectra and the dimeric models of AAA simulated using the semi-empirical PM3 method are in agreement with that proposal.