Synthesis, NMR data and theoretical study of semi-synthetic derivatives from trans-dehydrocrotonin

• Autor(a) principal: Soares, Breno Almeida
• Data de Publicação: 2015
• Outros Autores: Maciel, Maria Aparecida Medeiros, Castro, Rosane Nora, Kaiser, Carlos R., Firme, Caio Lima
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/handle/123456789/31554
• topic: t-DCTN; t-CTN; t-CTN-OL; NMR; QTAIM; DFT

In this work, the 19-nor-diterpenoid clerodane-type dehydrocrotonin (t-DCTN) was a primary source for a two-step synthetic procedure. The catalytic hydrogenation of t-DCTN afforded the semi-synthetic trans- crotonin (t-CTN) in a highly stereospecific reaction confirmed by DFT calculations. The unsaturated carbonyl group of t-DCTN was reduced by NaBH4/EtOH providing an epimeric a-OH and b-OH mixture named t-CTN-OL. Both epimeric compound structures t-CTN-a-OL and t-CTN-b-OL were elucidated by 1D and 2D NMR spectral data. Comparison of NMR data from natural source of t-CTN was done to confirm the stereochemical authenticity of semi-synthetic t-CTN. Calculated NMR data for all described de- rivatives (semi-synthetic t-CTN and its t-CTN-OL epimeric mixture) were performed using B3LYP/6- 311Gþþ(d,p) level of theory which validated our previously developed NMR theoretical protocol for structural analyses of organic molecules. Topological data using Quantum Theory of Atoms in Molecules (QTAIM) of t-CTN quantified and qualified intramolecular interactions of its most stable conformer