Journal of Chemical Reactivity and Synthesis
Volume:13 Issue: 3, Summer 2023

In the current research sodium silicate has been used to synthesize silica colloid by ion exchange process. Deterministic relations for zeta potential, size and solid content have been developed by optimization of three input parameters: seed concentration (0, 1, 2%wt), temperature (30, 55, 80°C) and KOH concentration (0.5, 1, 1.5%wt). Central Composite Design of Response Surface Methodology was used to optimize silica colloid. The goal of this optimization is to achieve the silica colloid with the highest zeta potential, the minimum particle size and the highest solid content. The derived equations and contour plots predict the values of selected independent variables for preparation of optimum silica colloid with desired properties. Based on the fitted models, the optimum silica colloid is prepared by 0.756%wt KOH in 70°C that contains 59.9 %wt SiO2. Also, this silica colloid sample contains a particle size of 11.5 nm and zeta potential of -6.48 mV.

 Heterocyclic compounds are widely distributed in nature and have played a vital role in synthetic organic chemistry. Five membered heterocycles, an important class of heterocyclic compounds, have been frequently synthesized and find a diverse range of applications in chemistry, biology and biochemistry of both pharmacological and chemical importance. Palladium-catalyzed cyclisation of different enynethiols has afforded a series of substituted thiophenes. The substrates, (Z)-2-en-4-yne-1- thiols, undergo cyclo isomerisation in dimethyl acetamide in the presence of catalytic amounts of PdI2 along with KI, to yield corresponding thiophenes 4 . Chiral imidazoles have been synthesized by thio-Ugi reaction . The method involves the treatment of thioamides with ammonia and cyclisation of the resulting substituted amidines in aqueous hydrochloric acid to afford corresponding imidazoles 11.This article will discuss on various synthetic pathways adopted for the synthesis of different five membered heterocycle derivatives and explore the mechanistic aspects apart from the recent applications of some unique compounds.

A new diamidophosphoester, (4-CH3-C6H4O)((CH3)2CHNH)2P(O), was synthesized from the reaction of freshly prepared (4-CH3-C6H4O)Cl2P(O) reagent and isopropylamine (1:4 mole ratio) in dry CH3CN. The prepared compound was characterized by IR, 1H-NMR, 13C{1H}-NMR and 31P{1H}-NMR spectroscopies. Two methyl groups of the NHCH(CH3)2 moiety are magnetically non-equivalent and are revealed in different chemical shifts in the 1H- and 13C-NMR spectra, but with equal hydrogen-hydrogen coupling constants in 1H-NMR (3J(H,H) = 6.4 Hz for both) and phosphorus-carbon coupling constants in 13C-NMR (3J(P,C) = 5.7 Hz for both). The NH protons reveal a triplet with apparent coupling constant of 10.1 Hz (due to geminal phosphorus-hydrogen and vicinal hydrogen-hydrogen couplings). The ipso and ortho carbon atoms of the 4-CH3-C6H4O moiety appear as doublets with 2J(P,C) = 6.5 Hz  3J(P,C) = 4.8 Hz. In the IR spectrum, the NH stretching vibrations appear at 3281 cm–1 and 3194 cm–1. The phosphorus chemical shift of the title compound was compared with some literature compounds to show the electronic and anisotropic effects of substituents attached to phosphorus.

In this research article, we report the preparation of from melamine-terephthalaldehyde supported Copper-1,2,4,5-tetrabenzenecarboxylic acid (COF-MOF) as a porous acidic catalyst for the one-pot preparation of 1,8-Dioxooctahydroxanthenes. As a new methodology, this strategy offers several advantages including green reaction conditions, high yield of the products, short reaction time, facile work-up, and recyclability of the catalyst.

In this research study, the Fe3O4@SiO2@CS@ PO(OH)2/Cu(II) core-shell nanoparticle serves as a highly effective magnetic catalyst. Its purpose is to efficiently convert a variety of alcohols, whether they contain electron-donating or electron-withdrawing groups, into their corresponding amine derivatives. Benzylamine and ammonia were employed as the amination agents. The optimization process studied various factors, including the presence and kind of a base, reaction temperature, time of reaction, type of transition metal, and amount of catalyst to identify the most favorable parameters. The optimal conditions were observed when using 0.3 mmol of catalyst liganded to Cu(II) under reflux conditions for a duration of 5-24 h corresponding to the substrate in the presence of K2CO3. The results of the study revealed that electron-donating groups have a positive impact on the reaction rate, whereas electron-withdrawing groups, such as nitro, negatively influence the overall yield. Additionally, this reaction process displayed remarkable efficiency. It offers exceptional practicality in organic chemistry and industrial applications, primarily due to the ease of separating the catalyst using an external magnetic field, its stability, and its ability to be reused multiple times.

Multicomponent reactions (MCRs) are important for the achievement of high levels of diversity, as they allow more than two building blocks to be combined in practical, time-saving one-pot operations, giving rise to complex structures by simultaneous formation of two or more bonds, according to the domino principle, higher productivity, simple procedures, facile execution, and play an important role in combinatorial chemistry. Among a large variety of nitrogen-containing heterocyclic compounds, heterocycles containing an urazole moiety are of interest because they constitute an important class of natural and non-natural products, many of which exhibit useful some biological as well as pharmaceutical activity. 1-hydroxy-2-naphtoic acid and 3-hydroxy-2-naphtoic acid as a ligand were applied for complexation with metal ions under different conditions. The lanthanides were used for the indication of oxygen of hydroxyl of the –COOH group in these compounds. In this work, an efficient, environmentally and high yielding procedure for the one-pot, three-component synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by condensation of dimedone, urazole, and aromatic aldehydes catalyzed by Cu (II) complex was equipped with 3-hydroxy-2-naphtoic acid ligand (Cu-HNA), as an ecofriendly catalyst with high catalytic activity and reusability at 100°C under solvent-free conditions is reported. The reaction proceeds to completion within 30–40 min in 82–92% yield.