Synthesis and biological evaluation of pyranocarbazole derivatives as Anti-tumor agents

Previously undescribed tetrahydroanthraquinones from Prismatomeris tetrandra (roxb.) K. Schum with antitumor cell proliferation activities

To find structurally previously undescribed compounds with pharmacological effects from Prismatomeris tetrandra (Roxb.) K. Schum (Rubiaceae), thirteen undescribed tetrahydroanthraquinones (1⎼13) named prisconnatanones J⎼V and seven known anthraquinones (14⎼20) were isolated and characterized. The structures of these compounds were elucidated by detailed spectroscopic analyses, and their absolute configurations were established by modified Mosher's method and ECD calculations. The antitumor cell proliferative activities of prisconnatanones J⎼V were determined. Among them, prisconnatanones J possessed high antitumor cell proliferation in HGC27 cells (IC50, 0.792 μM) by blocking HGC27 cells in the S phase and significantly inducing apoptosis in HGC27 cells. Prisconnatanone J has no cytotoxicity to normal gastric cells line (GES-1) at 10 μM and showed a considerable selectivity for HGC27 cells. Prisconnatanone J can potentially inhibit tumor cell proliferation and should be further investigated.

Trivalent Organostibines: Sb,N Ligands in Double N-Arylation of Primary Amines toward Functionalized Carbazoles

A Sb,N ligand (L-Sb) for Pd-catalyzed double N-arylation of primary amines was developed. This trivalent ligand L-Sb, containing a 5,6,7,12-tetrahydrodibenzo[c,f][1,5]azastibocine skeleton and stable under air and moisture, could be synthesized facilely on a gram scale from chlorostibine (1) and cyclopentylmagnesium bromide. L-Sb showed excellent catalytic performance in Pd2(dba)3-catalyzed double N-arylation of 2,2'-dibromo-1,1'-biphenyl (2) with primary amines (3), affording functionalized carbazoles in good yields. This Pd2(dba)3/L-Sb-catalyzed double N-arylation, the first example of the application of trivalent organostibines as a ligand in N-arylation, featured the following advantages: small catalyst loading, wide functional group tolerance, good yields, and ease of gram-scale synthesis.

Current status of carbazole hybrids as anticancer agents

The drug resistance and low specificity of current available chemotherapeutics to cancer cells are the main reasons responsible for the failure of cancer chemotherapy and remain dramatic challenges for cancer therapy, creating an urgent need to develop novel anticancer agents. Carbazole nucleus, widely distributed in nature, is a predominant feature of a vast array of biologically active compounds. Carbazole derivatives exhibited potential antiproliferative activity against different cancer cell lines by diverse mechanisms, inclusive of arrest cell cycle and induce apoptosis, and several anticancer agents are carbazole-based compounds. Thus, carbazole derivatives represent a fertile source for discovery of novel anticancer therapeutic agents. Over the past several years, a variety of carbazole hybrids have been developed as potential anticancer agents. The present review focuses on the recent progress, from 2016 until now, in knowledge on anticancer properties, structure-activity relationships and mechanisms of action of carbazole hybrids to provide a basis for development of relevant therapeutic agents.