Synthesis of 1,3-thiazines by a three-component reaction and their transformations into β-lactam-condensed 1,3-thiazine and 1,4-thiazepine derivatives

GRAPHICAL ABSTRACT

ABSTRACT

Variously substituted 1,3-thiazines have been prepared by a three-component reaction involving a thioamide, an aldehyde, and an alkene. Two diastereomeric thiazines were transformed by stereoselective Staudinger reaction into the corresponding chloro-β-lactam-condensed-1,3-thiazines, and one of them was rearranged in basic media to afford a highly substituted 1,4-thiazepine. Several of the obtained compounds (six 1,3-thiazines and one β-lactam-condensed-1,3-thiazine) were analyzed by X-ray crystallography, which enabled to assign their spatial arrangement and stereochemistry.

Keywords:

• Three-component reaction
• 1,3-thiazine
• Staudinger reaction
• β-lactam-condensed 1,3-thiazine
• 1,4-thiazepine

Acknowledgments

The authors thank Prof. A.-C. Gaumont, the director of their laboratory, for helpful discussions. R. Legay and K. Jarsalé are acknowledged for the NMR analyses and mass spectra, respectively.

Funding

The authors acknowledge for financial support (grant for F.P.) the Centre National de la Recherche Scientifique (CNRS) and the Région Basse-Normandie.