Synthesis of a New Library of Pyrano-phenazine Derivativesviaa Novel Three-Component Protocol

Introducing a green nanocatalytic process toward the synthesis of benzo[a]pyrano-[2,3-c]phenazines utilizing copper oxide quantum dot-modified core-shell magnetic mesoporous silica nanoparticles as high throughput and reusable nanocatalysts

In this contribution, a green, simple, efficient, and straightforward nanocatalytic process was developed for the synthesis of benzo[a]pyrano[2,3-c]phenazine derivatives under mild thermal conditions. In this regard, the copper oxide quantum dot-modified magnetic silica mesoporous nanoparticles (M-MSNs/CuO(QDs)) were synthesized by surface modification of M-MSNs with CuO QDs to prepare a highly powerful magnetic core-shell nanocatalyst. The prepared nanocatalyst was then characterized for its functionality, size, morphology, elemental composition, surface area, crystallinity, and magnetic properties. Afterwards, it was applied for the synthesis of benzo[a]pyrano[2,3-c]phenazine derivatives under green reaction conditions. The factors affecting the reaction yield were optimized by the one-factor-at-a-time optimization method. Under obtained optimal conditions, the developed method showed a reaction yield range as high as 86-95% for different derivatives. The reusability studies were performed for indexing the cycling stability of the prepared magnetic nanocatalyst. The results exhibited that the catalytic efficiency of the nanocatalyst was saved for at least 5 operational times, showing high cycling stability of M-MSNs/CuO(QDs). Finally, the catalytic performances of the nanocatalyst was compared with the reported ones, revealing that the M-MSNs/CuO(QDs) presents very better performances toward the synthesis of benzo[a]pyrano[2,3-c]phenazine derivatives than the reported ones.

A review on lawsone-based benzo[a]phenazin-5-ol: synthetic approaches and reactions

Phenazine systems are an important class of aza-polycyclic compounds that are easily found in nature and isolated as secondary metabolites primarily from Pseudomonas, Streptomyces, and a few other genera from soil or marine habitats. Moreover, various synthetic phenazine analogs are known for their pharmaceutical activities. Among various phenazines, benzo[a]phenazines are structural subunits in a variety of important natural products and have been given special attention due to their unique biological properties in various fields. In this review article, we highlight the synthesis of benzo[a]phenazin-5-ol derivatives from lawsone and benzene-1,2-diamines and their applications for the construction of a variety of five and six membered fused heterocycles such as pyranophenazines, spiropyranophenazines, pyridophenazines, furophenazines, benzochromenophenazines and oxazinophenazines during the period of 1995 to 2021.

Photochemical and electrochemical regioselective cross-dehydrogenative C(sp2)–H sulfenylation and selenylation of substituted benzo[a]phenazin-5-ols

The essence of photo- and electrochemistry: sulfenylation and selenylation of substituted benzo[a]phenazin-5-ols through cross-dehydrogenative C(sp2)–H functionalization.

Chitosan-attached nano-Fe3O4 as a superior and retrievable heterogeneous catalyst for the synthesis of benzopyranophenazines using chitosan-attached nano-Fe3O4

A simple and rapid method for the preparation of benzopyranophenazines is presented, involving a one-pot four-component reaction of hydroxynaphthoquinone, o-phenylenediamine, benzaldehydes, and malononitrile with nano-Fe3O4@chitosan as an efficient heterogeneous solid acid catalyst under reflux conditions in ethanol. The catalyst is characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), magnetic susceptibility measurements, energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared (FT-IR) spectroscopy. Atom economy, high catalytic activity, a wide range of products, excellent yields in short reaction times, and low catalyst loading are some of the important features of this method.

Recent developments in the isolation, biological function, biosynthesis, and synthesis of phenazine natural products

Phenazines are natural products which are produced by bacteria or by archaeal Methanosarcina species. The tricyclic ring system enables redox processes, which producing organisms use for oxidation of NADH or for the generation of reactive oxygen species (ROS), giving them advantages over other microorganisms. In this review we summarize the progress in the field since 2005 regarding the isolation of new phenazine natural products, new insights in their biological function, and particularly the now almost completely understood biosynthesis. The review is complemented by a description of new synthetic methods and total syntheses of phenazines.