Natural bond orbital analysis, salvation, and substituent effects of electron-releasing (–CH3, –OH) and electron-withdrawing (–Cl, –NO2, –CF3) groups at para positions on the molecular structure of synthesized 3-phenylbenzo[ d]thiazole-2(3 H)-imine and its derivatives in selected solvents (acetone, toluene, and ethanol) and in the gas phase by employing the polarizable continuum method model are studied using the M06-2x method and 6-311++G(d,p) basis set. The relative stability of the studied compounds is influenced by the possibility of intramolecular interactions between substituents and the electron donor–acceptor centers of the thiazole ring. Furthermore, atomic charges, electron density, chemical thermodynamics, energetic properties, dipole moments, and nucleus-independent chemical shifts of the studied compounds and their relative stability are considered. The dipole moment values and the highest occupied molecular orbital–lowest unoccupied molecular orbital energy gaps reveal different charge-transfer possibilities within the considered molecules. Finally, natural bond orbital analysis is carried out to picture the charge transfer between the localized bonds and lone pairs.

t h e s i s o f T e t r a h y d r o -d i h y d r o x y -o x o i n d e n o [ 1 , 2 -b ] p y r r o l e D e r i v a t i v e sAbstract: A new protocol for the synthesis of a series of tetrahydrodihydroxy-oxoindeno[1,2-b]pyrrole from simple primary amines, alkyl propiolates, and ninhydrin was developed. The key step in the synthesis is an efficient three-component reaction of an amine with an alkyl propiolate to give a 3-amino acrylate derivative, which then reacts with ninhydrin.Despite recent advances in molecular biology and the progress in combinatorial synthetic methodology, the rate of introduction of new pharmaceuticals has decreased markedly over the past two decades. 1a Structural diversity in a focused collection of potential therapeutics is believed to increase the positive hit rate. Most pharmaceuticals in use are still small synthetic organic molecules that often contain a heterocyclic ring. 1a-c However, the range of easily accessible and suitably functionalized heterocyclic building blocks for the synthesis of structurally diverse libraries is rather limited. The development of new, rapid, and clean synthetic routes toward focused libraries of such compounds is therefore of great importance to both medicinal and synthetic chemists. 1 Undoubtedly, the most efficient strategies involve multicomponent reactions (MCRs), which have become a powerful tool for the rapid introduction of molecular diversity. 2 Consequently, the design and development of MCRs for the generation of heterocycles have received increased interest. 2aPolyhydroxylated alkaloids are interesting heterocycles that can act as powerful and selective inhibitors of glycosidases and exhibit bactericidal, antidiabetic, and antiviral activities, 3,4 making these compounds good lead compounds for the development of new drugs for the treatment of viral infections, cancer, and diabetes. 3,4 Consequently, the development of general and facile methods for the synthesis of such compounds is an active field of research. 4-7 For example the tetrahydro-dihydroxy-oxoindeno[1,2-b]pyrrole system is of interest in connection with the search for potential oral hypoglycemic agents. 8As part of our general interest in MCRs, 9 our ongoing research programs in the area of heterocyclic compounds containing nitrogen, 9,10 and due to the resultant pharmacological interest in polyhydroxylated alkaloids, herein we report an efficient three-component method for the construction of new tetrahydro-dihydroxy-oxoindeno[1,2-b]pyrroles, via condensation of amines, alkyl propiolates, and ninhydrin (Scheme 1).In order to prove that b-aminoacrylates 5 exist as intermediates in this reaction, compound 5e (Z/E, 6:4) was synthesized separately by the condensation of benzyl amine and methyl propiolate, and then reacted with 3. The resulting product was identical to that formed in the three-component procedure.The reaction was carried out by the simple addition of one equivalent of primary amine to one equivalent of alkyl propiolate in water, followed by the addition of one equivale...

Abstract:A rapid and efficient solvent-free one-pot synthesis of coumarin derivatives by Pechmann condensation reactions of phenols with ethyl acetoacetate using FeF 3 as a catalyst under microwave irradiation is described. This one-pot synthesis on a solid inorganic support provides the products in good yields. The newly synthesized compounds were systematically characterized by IR, 1 H-NMR, 13 C-NMR, MS and elemental CHN analyses. The proposed solvent-free microwave irradiation method using the environmentally friendly catalyst FeF 3 offers the unique advantages of high yields, shorter reaction times, easy and quick isolation of the products, excellent chemoselectivity, and a one-pot, green synthesis. The products were screened for antimicrobial activity, and the results showed that the compounds reacted against all the tested bacteria.

We have developed herein a new approach to the diverse synthesis of novel derivatives of 3-aryl benzo[d]thiazole-2(3H)-imines (3a−g), by a two-component reaction between diazonium salt (2) and various synthesized N-acyl-N'-aryl thioureas (1a−g), in the presence of sodium tert-butoxide as strong base. Finally, it resulted in the production of the desired products with a moderate yield. The chemical structures of these synthesized compounds were confirmed by various physico-chemical methods viz. FT-IR, 1 H-NMR, 13 C-NMR, and elemental analysis.

A series of some new spiro‐1,4‐dihydropyridine derivatives have been synthesized in good yields in a four component, and solvent‐free process by condensation of isatins, primary amines, ethyl cyanoacetate and cyclohexanone on solid support montmorillonite K10