Current Organic Chemistry - Volume 26, Issue 9, 2022

Numbrino^TM, a nasal anesthetic solution based on cocaine hydrochloride, has recently been approved by the FDA for diagnostic procedures and surgery – now, what will be the role of the controlling agencies and the legislation of producing countries to face the imminent medicinal use of cocaine? Would chemistry be the protagonist in proposing alternative approaches to help and overcome this issue? The debate is open with this commentary.

In recent years, nitroarenes have been extensively exploited as green, efficient electrophilic arylation reagents used in a variety of organic syntheses. Transition-metal-free cross-coupling reactions and Vicarious Nucleophilic Substitution (VNS) have become practical and reliable synthetic methods to access momentous functionalized organic compounds. Thus, the introduction of various substituents into nitroarenes has attracted considerable attention as important synthetic approaches due to their simplicity and practicality. In this review, we comprehensively summarize the coupling of several carbon and nitrogen substituents with nitroarenes via nucleophilic substitution under mild conditions, followed by the application of these transversions in the construction of carbon and heterocyclic rings.

Spiropyrazoles display many biological activities such as antitumor, vasodilation, analgesic, phosphodiesterase inhibitors, aldosterone antagonistic, anabolic, androgenic, antiinflammatory, progestational and salt-retaining activities, and they also exert neuroprotection in dopaminergic cell death. Many efforts have been made to obtain these derivatives with high yield and excellent regio-, diastereo- and enantioselectivities. Most of the spiroprazole synthesis methods were proceeded in good to excellent yield in the presence of organic catalysts, such as squaramide, NHC pre-catalyst, pyrrole derivatives, bis-oxazoline, etc. DMAP, DABCO, thiourea derivatives, DBU, acetic acid and quinoline catalysts. In addition, the inorganic and organometallic catalysts have been proven their efficiency in the synthesis of various types of spiro-pyrazoles in excellent yield. Thus, in this review, we have compiled all citations for the synthesis of spiropyrazoles in the presence of various types of catalysts such as organic, inorganic, and metalorganic catalysts in the range 2020 to 2012. This review article is a useful compilation for researchers interested in the synthesis of spiropyrazole derivatives and will assist them in selecting appropriate catalysts for the preparation of their spiropyrazoles.

Over the past decades, the N-arylation of indoles has gained an inevitable role in the fields of material science, pharmaceuticals, and agrochemical industries. They are the basic core skeleton of many natural products. Their synthesis by Ullmann-type C-N coupling reaction of indole derivatives with aryl halides through various catalytic protocols is well explored. Transition metal catalysis was the best method for synthesizing 1-aryl indoles, and copper catalysis is the leading among them. This review comprehends the recent developments in the copper-catalyzed C-N cross-coupling of indoles with aryl halides from 2010 to 2022.

The discovery and synthesis of natural products, especially those possessing novel scaffolds, are crucial to the development of new drugs. Dracaenones are part of homoisoflavone natural products, owning a complex spiro-bridged polycyclic structure bearing benzylic quaternary carbon centers, and some of them reveal considerable biological activity. There have been continuous studies on these compounds due to the rare structure and important biological properties. However, a systematic summary and analysis for dracaenone is lacking. This review aims to generally summarize the natural source, synthetic strategies and biological activities of dracaenones, moreover, the limitations, challenges, and future prospects were discussed, wishing to provide references for the follow-up study of compounds with similar skeleton.