Stereochemical and 13C NMR study in order to characterize intermediates obtained by cyclisation of diisoxazoledilactone

Stereochemical and 13C NMR study in order to characterize intermediates obtained by cyclisation of diisoxazoledilactone

Amaral, André F. C.; Matos, Guilherme D. R.; Resck, Inês S.; Maia, Elaine R.

Abstract:

A ring-expansion synthesis from bicyclical enol-ethers can lead to surprises. From a standard procedure to synthesize (±)-pirenophorin, a unique molecule has been found, a diisoxazoledilactone (Figure 1). Racemic mixtures as dioximedilactones, diketodialctones and diisoxazoledilactone were observed on intermediate steps. Its components were characterized by chromatographic and spectrometric methods. In order to explain the formation of the oxazolinic rings, molecular dynamics (MD), Austin Model 1 (AM1) , density functional theory (DFT) and AM1 13C NMR simulations were performed in order to characterize stereochemistry of the intermediates and to verify if it is possible to predict isomerism from the chemical shifts variations by AM1.

A ring-expansion synthesis from bicyclical enol-ethers can lead to surprises. From a standard procedure to synthesize (±)-pirenophorin, a unique molecule has been found, a diisoxazoledilactone (Figure 1). Racemic mixtures as dioximedilactones, diketodialctones and diisoxazoledilactone were observed on intermediate steps. Its components were characterized by chromatographic and spectrometric methods. In order to explain the formation of the oxazolinic rings, molecular dynamics (MD), Austin Model 1 (AM1) , density functional theory (DFT) and AM1 13C NMR simulations were performed in order to characterize stereochemistry of the intermediates and to verify if it is possible to predict isomerism from the chemical shifts variations by AM1.

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DOI: 10.5151/chempro-14bmos-R0322-1

Referências bibliográficas

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• [4] 4 Materials Studio S/W. Acelrys, Inc., 10188 Telesis Court, Suite 100, San Diego, CA 92121, USA.

Como citar:

Amaral, André F. C.; Matos, Guilherme D. R.; Resck, Inês S.; Maia, Elaine R.; "Stereochemical and 13C NMR study in order to characterize intermediates obtained by cyclisation of diisoxazoledilactone", p-322-322. In: In Blucher Chemistry Proceedings, São Paulo, v. 1, n. 1, Setembro.2013. São Paulo: Blucher, 2013.
ISSN 23184043, DOI 10.5151/chempro-14bmos-R0322-1