Synthesis of indole derivatives as prevalent moieties present in selected alkaloids.

Indoles are a significant heterocyclic system in natural products and drugs. They are important types of molecules and natural products and play a main role in cell biology. The application of indole derivatives as biologically active compounds for the treatment of cancer cells, microbes, and different types of disorders in the human body has attracted increasing attention in recent years.

Copper-free Sonogashira cross-coupling reactions: an overview.

The Sonogashira reaction is a cross-coupling reaction of a vinyl or aryl halide with a terminal alkyne to form a C-C bond. In its original form, the Sonogashira reaction is performed with a palladium species as a catalyst while co-catalyzed by a copper species and a phosphine or amine. The reaction is conducted under mild conditions, , room temperature, aqueous solutions, and the presence of mild bases.

Prescribed drugs containing nitrogen heterocycles: an overview.

Heteroatoms as well as heterocyclic scaffolds are frequently present as the common cores in a plethora of active pharmaceuticals natural products. Statistically, more than 85% of all biologically active compounds are heterocycles or comprise a heterocycle and most frequently, nitrogen heterocycles as a backbone in their complex structures. These facts disclose and emphasize the vital role of heterocycles in modern drug design and drug discovery.

Application of The Dess-Martin Oxidation in Total Synthesis of Natural Products.

Dess-Martin periodinane (DMP), a commercially available chemical, is frequently utilized as a mild oxidative agent for the selective oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. DMP shows several merits over other common oxidative agents such as chromiumand DMSO-based oxidants; thus, it is habitually employed in the total synthesis of natural products. In this review, we try to underscore the applications of DMP as an effective oxidant in an appropriate step (steps) in the multi-step total synthesis of natural products.

Silver nanoparticles-decorated Preyssler functionalized cellulose biocomposite as a novel and efficient catalyst for the synthesis of 2-amino-4H-pyrans and spirochromenes.

Silver nanoparticles-decorated Preyssler functionalized cellulose biocomposite (PC/AgNPs) was prepared and fully characterized by FTIR, UV-vis, SEM, and TEM techniques. The preparation of PC/AgNPs was studied systematically to optimize the processing parameters by Taguchi method using the amount of PC, reaction temperature, concentration of silver nitrate and pH of medium. Taguchi's L9 orthogonal (4 parameters, 4 level) was used for the experimental design.

Applications of Cu(0) encapsulated nanocatalysts as superior catalytic systems in Cu-catalyzed organic transformations.

Recently, Cu nanoparticles (NPs) encapsulated into various materials as supports (, zeolite, silica) have attracted much devotion due to their unique catalytic properties such as high catalytic activity, intensive reactivity and selectivity through highly protective properties. Nowadays, the superior catalytic activity of Cu-NPs, encapsulated onto zeolite, silica and different porous systems, is extensively investigated and now well-established. As a matter of fact, Cu-NPs are protected from deactivation by this kind of encapsulation.

Recent applications of the Wittig reaction in alkaloid synthesis.

The Wittig reaction is the chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide (the Wittig reagent) to afford an alkene and triphenylphosphine oxide. Noteworthy, this reaction results in the synthesis of alkenes in a selective and predictable fashion. Thus, it became as one of the keystone of synthetic organic chemistry, especially in the total synthesis of natural products, where the selectivity of a reaction is paramount of importance.

Alkynes as Privileged Synthons in Selected Organic Name Reactions.

Background: Alkynes are actually basic chemicals, serving as privileged synthons for planning new organic reactions for assemblage of a reactive motif, which easily undergoes a further desirable transformation. Name reactions, in organic chemistry are referred to those reactions which are well-recognized and reached to such status for being called as their explorers, discoverers or developers. Alkynes have been used in various name reactions.

Cascade process for direct synthesis of indeno[1,2-b]furans and indeno[1,2-b]pyrroles from diketene and ninhydrin.

Novel and efficient multicomponent reactions (MCRs) involving diketene, ninhydrin (indane-1,2,3-trione) and one primary amine (3CR) or two different primary amines (4CR) were achieved for the successful synthesis of dihydro-4H-indeno[1,2-b]furan-3-carboxamides or tetrahydroindeno[1,2-b]pyrrole-3-carboxamides, respectively. The merits of this method are highlighted by using either commercially available or easily accessible starting materials, operational simplicity, facile workup procedure, efficient usage of all the reactants, tolerance of a variety of functional groups and ability to conduct under un-catalyzed reaction condition. The products were also isolated by just decantation of the solvent, and for the purification column chromatography was non-required.

Electrochemically Induced Diels-Alder Reaction: An Overview.

One of the most important name reactions in organic chemistry, is the Diels-Alder cycloaddition reaction. It is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile to construct a substituted cyclohexene derivative. It is the stereotypical example of a pericyclic reaction with a concerted mechanism.

Applications of Friedel-Crafts reactions in total synthesis of natural products.

Over the years, Friedel-Crafts (FC) reactions have been acknowledged as the most useful and powerful synthetic tools for the construction of a special kind of carbon-carbon bond involving an aromatic moiety. Its stoichiometric and, more recently, its catalytic procedures have extensively been studied. This reaction in recent years has frequently been used as a key step (steps) in the total synthesis of natural products and targeted complex bioactive molecules.

Electrochemically Induced Michael Addition Reaction: An Overview.

Due to its high potential for the formation of carbon-carbon bonds, Michael addition reaction is one of the closest reactions to the heart of synthetic organic chemists. Electrochemistry presents a very stimulating and divergent resource for selective oxidation and reduction in organic chemistry, generating activated species, for example radical anions or radical cations. In this review, we try to underscore usefulness of electrogenerated Michael addition reaction with the hope of encouraging synthetic organic chemists to contemplate it, as an efficient and green strategy when it is required in their designed multi-step reaction pathways.

Application of the Asymmetric Pictet-Spengler Reaction in the Total Synthesis of Natural Products and Relevant Biologically Active Compounds.

Tetrahydroisoquinolines are the framework of numerous natural products predominantly alkaloids, an important and one of the most wide spread families of naturally occurring compounds in the plant kingdom. Tetrahydroisoquinolines are commonly constructed through an old reaction, the so-called Pictet−Spengler Reaction (PSR). In this reaction, a β-aryl ethylamine undergoes an acid mediated condensation with a suitable aldehyde or ketone, followed by ring closure.

Application of asymmetric Sharpless aminohydroxylation in total synthesis of natural products and some synthetic complex bio-active molecules.

This report illustrates the applications of Asymmetric Sharpless Aminohydroxylation (ASAH) in the stereoselective synthesis of vicinal amino alcohols as important intermediates in the total synthesis of complex molecules and natural products with significant biological activities. The ASHA allows the regio- -selective synthesis of 1,2-amino alcohols reaction of alkenes with salts of -halosulfonamides, -amides and -carbamates employing osmium tetroxide (OsO) as an efficient catalyst. In this reaction, chirality is induced the addition of dihydroquinine- and dihydroquinidine as derived chiral ligands.

Current advances in the synthesis and biological potencies of tri- and tetra-substituted 1H-imidazoles.

In this report, we review the current chemistry progress and in particular the synthesis approaches of tri- and tetra-substituted imidazoles.

Aqua mediated synthesis of substituted 2-amino-4H-chromenes catalyzed by green and reusable Preyssler heteropolyacid.

A simple, clean and environmentally benign route to the synthesis of 2-amino-4H-chromenes is described using Preyssler type heteropolyacid, H(14)[NaP(5)W(30)O(110)], as a green and reusable catalyst in water. The products were obtained in very good yields.