Abstract
Background: One-pot reactions have gained considerable and wide range of interests in the field of chemistry due to their simplicity and economy. Comparing to the step-by-step reactions that involve the formation of individual bonds for a given target product, the greatest attribute of one-pot reactions, is the formation of several bonds in one-pot operation without intermediate isolation, reaction condition changing and further reagents adding.
Objective: We developed an one-pot, rapid, simple and eco-friendly synthetic strategy for benzothiazines, benzothiazoles and benzothiazpines through the interaction of o-aminothiophenol with ketones, nitriles and chalcones, respectively. Method: A mixture of o-aminothiophenol ketones, nitriles and chalcones was refluxed or stirred at room temperature in glacial acetic acid containing a catalytic amount of concentrated H2SO4 for 3h. Then, the resulting precipitate was collected by filtration, washed with water and crystallized from the appropriate solvent. Results: The interaction of o-aminothiophenol with aromatic and aliphatic ketones containing active -hydrogens afforded the corresponding 2H-benzo[1,4]thiazines and 4H-benzo[1,4]thiazines, respectively. Similarly, the cyclic ketones afforded the corresponding tricyclic compounds. Treatment of o-aminothiophenol with nitriles under the same reaction condition gave benzo[1,3]thiazoles. Further, cyclocondensation with chalcones under the same reaction condition at room temperature yielded the corresponding benzo[1,5]thiazepines. The reaction mechanism was investigated and the structures of all new compounds were elucidated using spectral analysis. Conclusion: An efficient, simple and environmentally friendly synthesis of benzothiazines, benzothiazoles and benzothiazepines in one-pot synthesis has been developed. With this catalytic reaction, a very cheap sulfuric acid was used as a catalyst.Keywords: o-aminothiophenols, benzothiazines, benzothiazoles, benzothiazepines, one-pot reaction, economic preparation.
Graphical Abstract
Call for Papers in Thematic Issues
Exploring the Role of Chemical Graph Theory in Advancing Current Organic Synthesis
Organic synthesis is a fundamental discipline in chemistry, crucial for the creation of complex molecules with diverse applications in pharmaceuticals, materials science, and beyond. However, the process of designing efficient synthetic routes for target molecules remains challenging. Chemical graph theory, a branch of theoretical chemistry, offers powerful tools for understanding ...read more
Photoswitches for Molecular Recognition
This Special Issue would cover the hot topics on synthesis and chemical and photophysical characterization of new photoswitchable derivatives and their applications on molecular recognition of metabolites and biological active compounds, both in physiological medium and in living cells. Photoswitches are compounds that can change their conformation or properties in ...read more
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