Background: Sulfur and nitrogen heterocyclic systems, especially benzothiazine
derivatives, play a vital role in the search for newer drugs due to a significant scientific
interest owing to their broad range of synthetic values, various routes, and
pharmacological properties. It is known that benzothiazines are divided into five units:
1,2-, 2,1-, 1,3-, 3,1-, and 1,4-benzothiazines. Incorporating two moieties (benzo and
thiazine) increases the biological activity of both, and thus their values synthesize new
heteropolycyclic systems. Considering their diverse roles in the biological area and
synthesis chemistry, huge effects have been found in developing novel and efficient
methodologies to synthesize various benzothiazine moieties with different
substitutions.
Methods: The present chapter comprises an inclusive vision of new and
straightforward synthetic strategies to afford benzothiazine and related systems. This
chapter covers various reactions for synthesizing benzothiazines, such as alkylation,
acylation, aroylation, halogenation, elimination, rearrangement, ring enlargement,
reduction, and oxidation. Besides, it also includes other reactions, like cyclization,
addition, condensation, cyclocondensation, metal/acid-catalyzed, hydrolysis,
aminolysis, hydrazinolysis, complexation, and enantio/regioselective. Moreover, many
benzothiazines have been evaluated for their therapeutic activity.
Result: The synthesis and chemical reactions of benzothiazines derivatives have been
reported. The preparation approaches of some compounds have been found to involve
many steps, and others one-pot, resulting in good to excellent yields. Also, many
synthesized compounds have shown medicinal properties, such as aldose reductase,anti-inflammatory, analgesic, antimicrobial, antibacterial, antifungal, anticancer,
antiviral, antioxidant, herbicidal, and anticarcinogenic, anti-tubercular, antianthelmintic, and antitumor probes.
Conclusion: The chapter covers various methods to synthesize benzothiazines and
their derivatives, thereby displaying their biological activities.
Keywords: Aldose Reductase, Anti-Inflammatory, Analgesic, Antibacterial, Antiviral, Anticarcinogenic, Alkylation, Benzothiazines, Cu-Catalyzed, Coupling, Herbicidal, Medicinal Properties, Meloxicam, Regioselectivity, Synthesis.
