Novel aminoalkylated azaphenothiazines as potential inhibitors of T98G, H460 and SNU80 cancer cell lines in vitro

NaOAc-Promoted [3+1+2] Annulation of O-Pivaloyl Oximes, Aldehydes, and 2-Methylbenzothiazole Salts: Synthesis of 1-Azaphenothiazines

This paper presents an efficient strategy for constructing 1-azaphenothiazines through the NaOAc-promoted [3+1+2] annulation of O-pivaloyl oximes, aldehydes, and 2-methylbenzothiazole salts. The reaction is conducted in ethanol and employs oxygen as the oxidant under catalyst-free conditions. The process is amenable to various O-pivaloyl oximes, 2-methylbenzothiazole salts, and aldehydes, affording the target products in satisfactory yields.

Expedition of sulfur-containing heterocyclic derivatives as cytotoxic agents in medicinal chemistry: A decade update

This review article proposes a comprehensive report of the design strategies engaged in the development of various sulfur-bearing cytotoxic agents. The outcomes of various studies depict that the sulfur heterocyclic framework is a fundamental structure in diverse synthetic analogs representing a myriad scope of therapeutic activities. A number of five-, six- and seven-membered sulfur-containing heterocyclic scaffolds, such as thiazoles, thiadiazoles, thiazolidinediones, thiophenes, thiopyrans, benzothiazoles, benzothiophenes, thienopyrimidines, simple and modified phenothiazines, and thiazepines have been discussed. The subsequent studies of the derivatives unveiled their cytotoxic effects through multiple mechanisms (viz. inhibition of tyrosine kinases, topoisomerase I and II, tubulin, COX, DNA synthesis, and PI3K/Akt and Raf/MEK/ERK signaling pathways), and several others. Thus, our concise illustration explains the design strategy and anticancer potential of these five- and six-membered sulfur-containing heterocyclic molecules along with a brief outline on seven-membered sulfur heterocycles. The thorough assessment of antiproliferative activities with the reference drug allows a proficient assessment of the structure-activity relationships (SARs) of the diversely synthesized molecules of the series.

Phenothiazines Modified with the Pyridine Ring as Promising Anticancer Agents

Azaphenothiazines are the largest and most perspective group of modified phenothiazines, and they exhibit variety of biological activities. The review sums up the current knowledge on the anticancer activity of isomeric pyridobenzothiazines and dipyridothiazines, which are modified azaphenothiazines with one and two pyridine rings, respectively, against 10 types of cancer cell lines. Some 10-substituted dipyridothiazines and even 10-unsubstituted parent compounds, such as 10H-1,9-diazaphenothiazine and 10H-3,6-diazaphenothiazine, exhibited very potent action with the IC50 values less than 1 µg/mL and 1 µM against selected cancer cell lines. The strength of the anticancer action depends both on the tricyclic ring scaffolds and the substituents at the thiazine nitrogen atom. The review discusses the kind of the substituents, nature of tricyclic ring scaffolds with the location of the azine nitrogen atoms, the types of the cancer cell lines, and the mechanism of action.

Azaphenothiazines - promising phenothiazine derivatives. An insight into nomenclature, synthesis, structure elucidation and biological properties

For the last two decades, classical phenothiazines have attracted attention of researchers, as the hitherto investigations have revealed many significant biological activities within this class of compounds, other than originally discovered neuroleptic ones. Important, new pharmaceutical results on phenothiazines, as 10-substituted dibenzothiazines, were recently highlighted in several reviews. Azaphenothiazines are structurally modified phenothiazines by substitution of one or both benzene rings in the phenothiazine ring system with the azine rings, such as: pyridine, pyridazine, pyrimidine, pyrazine, 1,2,4-triazine, quinoline, quinoxaline, benzoxazine and benzothiazine. They form over 50 different heterocyclic systems, of tri-, tetra-, penta- and hexacyclic structures, and contain from one to even four azine nitrogen atoms. This review summarizes the methodical knowledge on azaphenothiazines, referring to their nomenclature, synthesis, structure analysis and above all significant varied biological activities, examined in vitro and in vivo. It describes, in addition, current trends in the synthesis of azaphenothiazines. The influence of the azaphenothiazine ring system, the nature of the substituents, predominantly at the thiazine nitrogen atom, as well as at the azine nitrogen atom and carbon atom, on the biological activities, were also discussed.