Mini-Reviews in Organic Chemistry - Volume 17, Issue 3, 2020

The benzofuranyl motif present in compounds exhibits various medicinal properties and non-drug applications. These derivatives are naturally occurring compounds or synthetic materials, which cover a broad spectrum of pharmacological activities like anti-inflammatory, anti-diabetic, anti- depressant, anti-HIV, anti-microbial, anti-proliferative, anti-convulsant, cytotoxic, analgesic, etc. Few of the commercially interesting compounds from this class are, ailanthoidol (anti-inflammatory), amiodarone, dronedarone, celivarone (anti-arrhythmic), bufuralol (muscular airways relaxant), morphine, 5-(2-aminopropyl)benzofuran; 5-APB, 6-(2-aminopropyl)benzofuran; 6-APB (CNS), rifampicin (antibiotic), etc., whereas, some of the non-drug applications are in perfumery industry (bergapten) and as tannin activators in sunscreen preparations (psoralen, 8-methoxypsoralen, and angelicin). Considering these interesting biological activities and commercial utilities, a review on the synthetic aspects of this privileged scaffold was attempted. For the benefit of natural product-based drug discovery, available sources of these derivatives, extraction process and reported biological activities have also been outlined in this review.

In the herbal drug pharmaceutical industry, guggul is enjoying emergent consumer acceptance around the world. In the Indian market, more than fifty formulations of guggul have been introduced by well-known brands including Himalaya, Patanjali and Baidyanath Pharmaceuticals. Basically, guggul is the gum resin from Commiphora wightii (syn. Commiphora Mukul). It has been used to treat various ailments including obesity, osteoarthritis, arthritis, constipation, liver disorders, inflammation, anemia, diabetes, etc. Including medicinal properties, it is used as a good binding agent and mixed in various herbal formulations. To review the major phytochemical, medicinal properties and analytical methods involved in the detection of guggul by using the exhaustive bibliographic research by means of various scientific engines and databases. Guggul contained approximately 66 phytochemical including gallic acid, quercetin, and guggulsterones E and Z. These phytochemicals have a wide range of pharmacological activities such as antioxidant, antibacterial, antimutagenic, antivenom and antitumor. It has been noticed that the mode of action of guggulsterone has not been fully explored. Pharmacology and toxicological studies are very few. These works have shown huge literature gap, which is to be fulfilled through the detailed in-vivo and in-vitro studies.

Micellar chemistry is gaining considerable interest among organic chemists because these reactions are carried out in environmentally benign solvents like water. Owing to the exhaustive use of toxic solvents in carrying out the different chemical reactions, there is a pressing need for alternative approaches either environmental friendly or having minimum impact on the environment. In this article, we aim to discuss the various aspects of micellar chemistry viz-a-viz its role in guiding the chemical reactions. Micelles help to drive various kinds of organic reactions including oxidations, reductions, carbon-carbon bond formation, carbon-heteroatom bond formation, multi-component reactions, Pd-coupling reaction, olefin metathesis reaction, Morita-Baylis-Hillman reaction, etc. in water.

Henry reaction is an important reaction employing carbonyls which furnishes β-nitro alcohol, nitroalkene, α-nitro ketones, β-amino alcohol as products and byproducts that may be transfigured as building blocks for other synthetic reactions. This paper focuses on various synthetic routes for Henry reaction, a versatile reaction of high significance in organic synthesis. The paper discusses the chemistry and plausible products of the reaction, along with the various available synthetic routes for the same, ranging from classical conventional methods to modern methods of green chemistry trends. Use of various catalysts as rate enhancer as well as use of various catalysts as enantioselective frontman for stereoselective reactions, have been described in this work.

Heliannuols are an important class of compounds isolated from Helianthus annuus, a common sunflower, with allelopathic properties. Interestingly, two of these fourteen compounds have been isolated from a gorgonian, Pseudopterogorgia rigida. This review compiles data on the isolation and biological activity of heliannuols described in the literature and briefly reports the papers describing their syntheses. This review could stimulate research into other natural species and syntheses. Further, it describes the 1H and 13C-NMR spectral data described in the literature for the 14 heliannuols already isolated and correlates them with their respective structures. Therefore, we believe that these searchable data enable a rapid identification in routine analysis of the crude extracts of sunflowers or gorgonians.

Benzothiazole (1, 3-benzothiazole) is one of the heterocyclic compounds, which is a weak base having varied biological activities. The unique methine center present in the thiazole ring makes benzothiazole as the most important heterocyclic compound. It is a common and integral structure of many natural and synthetic bioactive molecules. Benzothiazole derivatives show a variety of activities, with less toxic effects and their derivatives showed enhanced activities, which has proven Benzothiazole scaffold as one of the important moieties in medicinal chemistry. Benzothiazole ring containing compounds possess various pharmacological activities such as anti-viral, anti-microbial, antiallergic, anti-diabetic, anti-tumor, anti-inflammatory, anthelmitic and anti-cancer, which makes benzothiazole a rapidly developing and interesting compound in the medicinal chemistry. This review briefly explains the importance, common methods of synthesis of the benzothiazole scaffold and also explains the popular benzothiazole molecules which have applications in various fields of chemistry. A review has been carried out based on various pharmacological activities containing benzothiazole moieties and rationalize the activities based on the structural variations. Literature on benzothiazole derivatives reveals that substitution on the C-2 carbon atom and C-6 are the reasons for a variety of biological activities.