الفهرس 
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Abstract
The increasing demand for economical and environmentally friendly synthesis is a major challenge of modern chemistry. Therefore, the development of time-, energy-, and material-saving one-pot syntheses is an active research area. Zinc chloride is an inexpensive and easily available Lewis acid catalyst, it has been widely used in organic synthesis. However, it suffers from the serious drawback of being highly hygroscopic in nature so that it always needs to be fused prior to use and requires highly anhydrous conditions; it also produces exogenous wastes. These issues make the work-up process cumbersome. Therefore, we have prepared a silica-ZnCl2 reagent by Upadhyaya method which can find application as a user-friendly catalyst. Accordingly, the present survey is emphasized on the synthetic xanthene derivitives, 1,8-dioxodecahydroacridines derivatives, bis(indolyl) methane, N,N’-alkylidene bisamides, and amidoalkyl naphthols using SiO2-ZnCl2 (silzic) as solid catalyst. SECTION 1: A green synthesis of 14-aryl-14H- dibenzo[a,j]xanthenes and 1,8-dioxooctahydroxanthenes by silzic I-I) Condensation reaction of β–naphthol and aromatic aldehydes under solvent-free conditions: Xanthene and dibenzoxanthene derivatives are important heterocyclic compounds because of their wide range of therapeutic and pharmacological properties such as antibacterial, antiviral, anti-inflammatory activities. Different procedures have been used to produce xanthenes and benzoxanthenes, and this includes the reaction of aryloxymagnesium halides with triethylorthoformate, cyclodehydration, intramolecular phenyl carbonyl coupling reactions of benzaldehydes and acetophenones. Also, several reactions have been improved by the condensation of β–naphthol with aldehydes in the presence of catalyst, such as p-TSA, sulfamic acid, cyanuric chloride, LiBr and other. However, many of these methods have drawbacks such as long reaction time, unsatisfactory yields, and harsh reaction conditions. I-II) Condensation reactions of dimedone with aromatic aldehydes under solvent-free conditions : 1,8-dioxooctahydroxanthenes were also prepared by the use of NaHSO4-SiO2 (or) silica chloride, BiCl3, HClO4-SiO, LiBr and other. Herein, we describe an efficient method for the synthesis of 1,8- dioxo-octahydroxanthenes by condensation of dimedone and aromatic aldehydes using SiO2-ZnCl2 (silzic) under solvent-free conditions. SECTION ІІ : One-Pot synthesis of 1,8-dioxo-decahydroacridines utilizing silica-supported zinc chloride under solvent-free conditions : 1,8- dioxodecahydroacridines derivatives have been shown to have very high lasing efficiencies and used as photo initiators. Very few methods are known in the literature for the synthesis of acridinediones. The most straightforward synthesis of this compounds involve the three-component condensation of aldehydes, dimedone, and ammonium acetate or appropriate amines in the presence of several catalysts such as Amberlyst-15, FeCl3-SiO2, Proline, Acidic Ionic Liquids. SECTION ІІІ : An efficient synthesis of bis(indolyl) methanes and N,N’-alkylidene bisamides using silzic: ІІІ.І- An efficient synthesis of bis(indolyl) methanes using silzic: Bis (indolyl) alkanes and their derivatives containing two indole or substituted indoles constitute bioactive metabolites of terrestrial and marine origin. The most active cruciferous substances for promoting beneficial estrogen metabolism in men and women are bis(indolyl)methane, which induces apoptosis in human cancer cells. ІІІ.ІІ – Ann efficient synthesis of N,N’-alkylidene bisamides using silzic : Symmetrical and unsymmetrical N,N’-alkylidene bisamides and their derivatives are found as key structural sub-units for the construction of peptidomimetic frameworks SECTION IV: SiO2/ZnCl2-Catalyzed one-pot synthesis of amidoalkyl naphthols under solvent-free conditions, cyclization to 1,4-oxazepin-3(4H)-one IV-I Silica supported zinc chloride catalyzed preparation of amidoalkyl naphthols under solvent-free conditions : 1-Amidoalkyl naphthols can be converted to useful and important biological building blocks such as 1-amino methyl 2-naphthols by an amide hydrolysis reaction, since, these compounds exhibit depressor and bradycardia effects in humans.1-Amidoalkyl naphthols was prepared by multicomponent condensation of aldehydes, 2-naphthols and acetonitrile or different amides in the presence of Lewis or Bronsted acids. IV-II Syntheses of 1,4-oxazepin-3 (4H)-one via cyclization of 2-chloroacetamidoalkyl naphthols: Seven-membered ring systems containing two heteroatoms, e.g., benzothiazepines (N and S) and benzoxazeoines (N and O), are of considerable interest. Benzoxazepines, naphthoxazepines and their derivatives have some important biological and pharmacological activities such as on the central nervous system as enzyme inhibitors analgesic, antipsychotics and antidepressant. Some oxazepines and benzoxazepines were synthesized from amides, amino acids, esters, acid chlorides, flavones, amines and Mannich base.