Synthesis of Pharmacologically Active Bis(indolyl) and Tris(indolyl) Derivatives Using Chlorotrimethylsilane

Chlorotrimethylsilane is found to be a comparatively fast and efficient catalyst for carrying out electrophilic substitution reactions of indoles with various aldehydes/ketones/triethylorthoformate, yielding excellent amount of bis(indolyl)methanes/tris(indolyl)methanes. The merits of this protocol are avoidance of any external energy source, minimal reaction time, simple and easy procedure and high yield under solvent free room temperature condition. The versatility of this method has been tested with various aldehydes/ketones and received satisfactory results.     

One‐pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones Catalysed by Cupric Acetate under Solvent‐free Conditions

A solvent‐free synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones from aromatic aldehydes, β‐keto ester/acetyl acetone and urea catalysed by cupric acetate under thermal condition is reported as a simple and an efficient protocol. Compared with classical Biginelli reaction reported in 1893, this new method provides much improved modification in terms of yield and reaction time. The usage of milder catalyst, environmental friendly procedures and excellent yields within a very short time (5–15 min) are the advantages of the method in which the involvement of solvent‐free condition adds an edge to the method. Thus, the efficiency of the protocol enabled the rapid synthesis of 3,4‐dihydropyrimidin‐2(1H)‐one derivatives in a short duration.     

Organocatalytic Green Approach Towards the Fabrication of Fused Benzo N,N‐containing Heterocycles Facilitated by Ultrasonic Irradiation

The development of a metal‐free protocol for transformations in organic synthesis offers a significant potential environmental benefit. This article reports the exploration of meglumine, a nontoxic and biodegradable amino sugar, as an organocatalyst for the synthesis of biologically active 1H‐dibenzo[b,e][1,4]diazepin‐1‐ones, highly regioselective benzimidazole derivatives and derivatives of quinoxalines. Operational simplicity, mild reaction conditions, shorter reaction times, and use of green solvents are the highlights of this protocol. The advantage of ultrasonic irradiation has been significantly explored for the synthesis of the aforesaid compounds. Furthermore, the multifaceted use of o‐phenylenediamine has also been accentuated in the study.     

Facile Synthesis of 1,2-Disubstituted Benzimidazoles Usingp-Toluenesulfonic Acid through Grinding Method

Russian Journal of Organic Chemistry - An efficient synthetic method for the highly selective synthesis of pharmacologically active 1,2-disubstituted benzimidazole derivatives...     

Reaction of selenium dioxide with aromatic ketones in the presence of boron triflouride etherate: a protocol for the synthesis of triarylethanones

An efficient regioselective protocol for the C-C bond formation by the unexpected α,α-diarylation of aromatic ketones with unactivated arenes in the presence of selenium dioxide and boron trifluoride etherate has been developed. The generality and functional tolerance of this protocol is demonstrated by the synthesis of a series of triarylethanones.     

Triethylbenzylammonium Chloride as a Useful and Efficient Catalyst for the Alkylation of Indole/substituted Indoles in Water: A Comparative Study between Conventional and Microwave Irradiation

A green and facile method for the alkylation of indole/substituted indole in water using a phase Transfer catalyst (Triethylbenzylammonium Chloride, TEBA) to synthesise bis‐indolyl methanes (BIMs) and Michael addition of indole to α,β‐unsaturated carbonyl compounds is reported. The substitution of indoles occurred exclusively at the 3‐position and products of N‐alkylation has not been observed. However, for 3‐substituted indoles, reactions were found to occur at the 2‐position. A comparative study between conventional heating and microwave irradiation has also been reported.     

Microwave-assisted synthesis of benzo[4,5]imidazo[1,2-a]pyrimidines and pyrano[4,3-b]pyrans catalyzed by L-glutamine functionalized magnetic nanoparticles in water:ethanol mixture

In this work, we report an effective, one-pot syntheses of benzo[4,5]imidazo[1,2-a]pyrimidine and pyrano[4,3-b]pyran derivatives using L-glutamine functionalized nanoparticles (Fe₃O₄@SiO₂@L-glutamine NPs) under microwave irradiation. The organo-nanocatalyst underwent characterization through diverse techniques, including FT-IR, p-XRD, SEM, TEM, EDX, XPS, TGA, and VSM. Microwave irradiation and multicomponent reactions synergistically yield excellent product yields (≈80%–95%) in shorter reaction times (≈6–15 min) with a broader substrate scope. The organo-nanocatalyst displays notable catalytic efficacy, evidenced by high turnover numbers (TON) and turnover frequencies (TOF) across syntheses. This innovative protocol showcases exceptional efficiency, cost-effectiveness, and environmental friendliness, with advantages like minimal reaction conditions, easy catalytic recovery, recyclability, operational simplicity, and the use of eco-friendly solvents.     

KHSO4-Assisted Michael Addition–Elimination Reactions of Indole with 3-Dimethylamino-1-phenylprop-2-en-1-ones in Water: An Environmentally Friendly Synthesis of Novel 3-Indolylchalcones

KHSO₄-assisted Michael addition–elimination reactions of 2-methylindoles and 1,2-dimethylindoles with 3-dimethylamino-1-phenylprop-2-en-1-ones (2) in water, leading to the formation of 3-(2-methyl-1H-indol-3-yl)-1-arylpropenones (3a–e) and 3-(1,2-dimethy-1H-lindol-3-yl)-1-arylpropenones (3f–j) respectively in good to excellent yields have been reported. However, cyclodehydration of adducts 3a–f to give carbazoles 4 failed to take place under the reaction conditions.

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