First Vilsmeier-Haack Synthesis of Flavones usingbis-(Trichloromethyl) Carbonate/Dimethylformamide

Flavones as a Privileged Scaffold in Drug Discovery: Current Developments

BACKGROUND

Flavones are one of the main subclasses of flavonoids with diverse pharmacological properties. They have been reported to possess antimalarial, antimicrobial, anti-tuberculosis, anti-allergic, antioxidant, anti-inflammatory activities, among others.

OBJECTIVE

The present review summarizes the recent information on the pharmacological properties of naturally occurring and synthetic flavones.

METHODS

Scientific publications referring to natural and synthetic flavones in relation to their biological activities were hand-searched in databases such as SciFinder, PubMed (National Library of Medicine), Science Direct, Wiley, ACS, SciELO, Springer, among others.

RESULTS

As per the literature, seventy-five natural flavones were predicted as active compounds with reference to their IC50 (<20 µg/mL) in in vitro studies. Also, synthetic flavones were found active against several diseases.

CONCLUSION

As per the literature, flavones are important sources for the potential treatment of multifactorial diseases. However, efforts toward the development of flavone-based therapeutic agents are still needed. The appearance of new catalysts and chemical transformations is expected to provide avenues for the synthesis of unexplored flavones, leading to the discovery of flavones with new properties and biological activities.

One-Pot Cascade Heterocyclization of γ- and β-Ketomalononitriles to 2,4-Dichloro-Substituted Pyrano[2,3- d]pyrimidines and Furo[2,3- d]pyrimidines Mediated by Triphosgene and Triphenylphosphine Oxide

A one-pot cascade heterocyclization strategy has been developed for the synthesis of 2,4-dichloro-substituted pyrano[2,3- d]pyrimidines and furo[2,3- d]pyrimidines from linear γ- and β-ketomalononitriles using triphosgene and triphenylphosphine oxide. The reaction afforded synthetic useful products with moderate to good yields, bypassing the conventional harsh conditions of chlorination. The mechanistic study revealed that the reaction proceeded with a non-isocyanate route, and the second step may conduct in a triphenylphosphine oxide-catalyzed manner.

Flavones: an important scaffold for medicinal chemistry

Flavones have antioxidant, anti-proliferative, anti-tumor, anti-microbial, estrogenic, acetyl cholinesterase, anti-inflammatory activities and are also used in cancer, cardiovascular disease, neurodegenerative disorders, etc. Also, flavonoids are found to have an effect on several mammalian enzymes like protein kinases that regulate multiple cell signaling pathways and alterations in multiple cellular signaling pathways are frequently found in many diseases. Flavones have been an indispensable anchor for the development of new therapeutic agents. The majority of metabolic diseases are speculated to originate from oxidative stress, and it is therefore significant that recent studies have shown the positive effect of flavones on diseases related to oxidative stress. Due to the wide range of biological activities of flavones, their structure-activity relationships have generated interest among medicinal chemists. The outstanding development of flavones derivatives in diverse diseases in very short span of time proves its magnitude for medicinal chemistry research. The present review gives detail about the structural requirement of flavone derivatives for various pharmacological activities. This information may provide an opportunity to scientists of medicinal chemistry discipline to design selective, optimize as well as poly-functional flavone derivatives for the treatment of multi-factorial diseases.