Base-promoted Cyclization Reaction of o-Isothiocyanato Arylacetylenes and Aroylacetonitriles: Easy Access to Benzo[d][1,3]thiazines

A green and efficient synthesis of benzo[d][1,3]thiazines through base-promoted cyclization reaction of o-isothiocyanato arylacetylenes with aroylacetonitriles has been developed. This protocol displays high step economy and efficiency, and tolerates various...

1,5-Benzoxazepines as a unique and potent scaffold for activity drugs: A review

Benzoxazepines constitute a huge number of organic compounds widely described in the literature. Many of them are distinguished by their biological properties. Among them, our attention was drawn to 1,5-benzoxazepine derivatives due to their interesting pharmacological properties. As is reported in the literature, these compounds are not only good building blocks in organic synthesis but also have interesting biological and pharmacological properties. This article is the first review publication to describe the synthesis methods and unique properties of 1,5-benzoxazepines. Literature reports widely describe the biological properties of 1,5-benzoxazepine, like anticancer, antibacterial, or antifungal activities. 1,5-Benzoxazepine derivatives can also interact with G-protein-coupled receptors and could be incorporated into new potential drugs, among others, in treating neuronal disorders like Alzheimer's and Parkinson's disease.

Synthesis, Biological and Computational Evaluation of Novel 2,3-dihydro-2-aryl-4-(4- isobutylphenyl)-1,5-benzothiazepine Derivatives as Anticancer and Anti-EGFR Tyrosine Kinase Agents

BACKGROUND

Despite the availability of a variety of chemotherapeutic agents, cancer is still one of the leading causes of death worldwide because of the problems with existing chemotherapeutic agents like objectionable side effects, lack of selectivity, and resistance. Hence, there is an urgent need for the development of novel anticancer agents with high usefulness, fewer side effects, devoid of resistance and superior selectivity.

OBJECTIVE

The objective of this study is to synthesize a series of novel 1,5-benzothiazepine derivatives and evaluate their anticancer activity employing biological and computational methods.

METHODS

Twenty new benzothiazepines (BT1-BT20) were prepared by condensing different 1-(4- isobutylphenyl)ethanone chalcones with 2-amiothiophenol and evaluated for their anticancer activity by MTT assay against three cell lines including HT-29 (colon cancer), MCF-7 (breast cancer) and DU-145 (prostate cancer). These compounds were also tested for their inhibitory action against EGFR (Epidermal Growth Factor Receptor) tyrosine kinase enzyme by taking into account of their excellent action against colon and breast cancer cell lines. Further, the structural features responsible for the activity were identified by Pharmacophorebased modelling using Schrodinger's PHASETM software.

RESULTS

Among the 20 benzothiazepine derivatives, three compounds viz., BT18, BT19 and BT20 exhibited promising activity against the cell lines tested and the activity of BT20 was more than the standard methotrexate. Again the above three compounds showed excellent inhibitory activity with the percentage inhibition of 64.5, 57.3 and 55.8 respectively against EGFR (Epidermal Growth Factor Receptor) tyrosine kinase. PHASE identified a five-point AHHRR model for the proposed activity and the computational studies provided insights into the structural requirements for the anticancer activity and the results were consistent with the observed in vitro activity data.

CONCLUSION

These novel benzothiazepines will be useful as lead molecules for the further development of new cancer therapies against colon and breast cancers.

tert-Amino Effect-Promoted Rearrangement of Aryl Isothiocyanate: A Versatile Approach to Benzimidazothiazepines and Benzimidazothioethers

A general and practical approach to benzimidazothiazepine and benzimidazothioether derivatives via an intramolecular nucleophilic addition/ring expansion rearrangement of aryl isothiocyanates promoted by the tert-amino effect has been developed. This reaction is catalyzed by low-cost camphorsulfonic acid and tolerates a broad substrate scope with complete atom economy. Structurally intriguing benzimidazothiazepine and benzimidazothioether products could be easily obtained by a simple operation in good to excellent yield (up to 98%).

Recent advances in transition-metal-catalyzed reactions of alkynes with isoxazoles

Isoxazoles, as masked 1,3-dicarbonyl equivalents, have proven to be versatile building blocks and pivotal intermediates for the construction of a variety of useful azacycles with molecular complexity. As a result, a range of new reactions have been discovered based on isoxazoles in the past decade. However, the relevant reactions of isoxazoles with alkynes have seldom been explored. In this review, we will focus on the recent progress in the transition-metal-catalyzed formal annulations for the efficient synthesis of N-heterocycles between alkynes and isoxazoles by highlighting their specificity and applicability, and the mechanistic rationale is presented where possible.

Thiosulfonylation of alkenes with the insertion of sulfur dioxide under non-metallic conditions

A three-component reaction of 1-(2-allylaryl)thioureas, sulfur dioxide, and aryldiazonium tetrafluoroborates under mild conditions is realized, leading to sulfonated [3,1]-benzothiazepines in good yields. High efficiency is observed for this non-metallic transformation.

A Fluorination/Aryl Migration/Cyclization Cascade for the Metal-Free Synthesis of Fluoro-Benzoxazepines

Fluorinated organic molecules are of high interest for many applications across chemical and medical disciplines. Efficient methods for the synthesis of such compounds are thus needed. Within this work, application of the bench-stable cyclic hypervalent iodine(III) fluoro reagent 1 facilitated the development of an efficient, metal-free method for the preparation of the novel class of 4-fluoro-1,3-benzoxazepines starting from readily available styrenes. The efficacy and broad applicability of this concept is demonstrated by the synthesis of 20 structurally diverse congeners in high yields, regio-, and diastereoselectivities. The presented method provides complementary chemoselectivity when compared to the common, commercially available electrophilic fluorination reagents, such as selectfluor. First mechanistic investigations with isotopically labeled substrates reveal a complex reaction mechanism, proceeding via an unusual fluorination/1,2-aryl migration/cyclization cascade.