N-bridged heterocycles: regiospecific synthesis of 2-methyl-4H-pyrimido[2,1-b]benzothiazol-4-ones

A Review on Medicinally Important Heterocyclic Compounds

Heterocyclic compounds account for the most prominent and diverse class of organic compounds. A significant number of heterocyclic compounds have been synthesized up to this point. Heterocyclic compounds are rapidly increasing in number due to extensive synthetic research and also their synthetic utility. Such compounds have a wide range of uses in the field of medicinal chemistry. Dyestuff, sanitizers, corrosion inhibitors, antioxidants, and copolymer synthesis are additional well-known applications. There are always distinguishing characteristics of an efficient approach for producing newly discovered heterocyclic compounds and their moieties. According to prior research, more than 90% of medicines containing heterocyclic compounds have been developed after the obtainment of a thorough scientific grasp of the biological system. It was discovered in the neoteric developments of heterocyclic compounds that these play a vital role in curative chemistry, and exert anticancer, anti-inflammatory, antifungal, antiallergic, antibacterial, anti-HIV, antiviral, anti-convulsant, and other biological activities. The present article provides detailed information regarding such heterocyclic compounds.

Recent advances in the synthesis of benzothiazole and its derivatives

Abstract:

Benzothiazoles have recognized pharmacophores in the field of research, predominantly in synthetic and medicinal chemistry, on account of their significant pharmaceutical properties. This important class of derivatives endows an extensive range of biological activities like anti-inflammatory, antidiabetic, anticancer, anticonvulsant, antibacterial, antiviral, antioxidant, antituberculosis, enzyme inhibitors, etc. Hence, various methodologies have been accomplished to synthesize benzothiazole compounds considering the purity, yield, and selectivity of the products. This review provides different reaction methods that are involved in the synthesis of a variety of benzothiazole derivatives.

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

Two regiodivergent approaches to intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and amides have been developed, controlled by the reagents employed. With the Brønsted base KOt-Bu and CBrCl3 as radical initiator, benzo[d]imidazo[2,1-b]thiazoles are synthesized via attack at the α-carbon and keto carbon of the β-ketoester moiety. In contrast, switching to the Lewis acid catalyst, In(OTf)3, results in the regioselective nucleophilic attack at both carbonyl groups forming benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones instead.

Synthesis of new compounds related to the commercial fungicide tricyclazole

BACKGROUND

Tricyclazole is a commercial fungicide used to control rice blast. As part of re-registration activities, samples of metabolites and process impurities are required. In addition, isotopically labeled tricyclazole samples are also required.

RESULTS

Four new compounds related to tricyclazole are reported. An isotopically labeled sample of tricyclazole was prepared that contained two (15)N atoms and one (13)C atom. Radiolabeled tricyclazole with (14)C at the triazole C3 position was also synthesized. A new process impurity in technical tricyclazole was identified and synthesized. A new metabolite of tricyclazole was identified, independently synthesized and characterized by X-ray crystallography.

CONCLUSION

A previously unreported metabolite of tricyclazole has been identified and structurally characterized. In addition, a new process impurity has been identified by independent synthesis. Identification of these new compounds has facilitated the continued registration of this important fungicide.