Abstract: The present investigation is concerned with the synthesis of acid azo dye based on 1-Amino-2-naphthol-6-nitronaphthalene-4-sulphonic acid and its chromium, iron, cobalt, nickel and copper complexces. The structure of these complexes were analyzed by UV-Visible, FTIR, NMR and elemental analysis. The synthesized dyes were applied on leather to assess its fastness properties. The thermal stability have been analyzed by thermal gravimetric analysis where the dyes were stable up to 250 ̊C. The antifungal activities of the azo ligands and its metal chelates were studied against Candida albicans.

ABSTRACT Starting from ibuprofen, a non-steroidal anti-inflammatory drug, N,N’-disubstituted thiourea derivatives were synthesized by refluxing the acid chloride of ibuprofen with potassium thiocyanate followed by substituted anilines to get N-2-(4-(2-methylpropyl)phenyl)propionoyl-N’-(2’-bromophenyl) thiourea (1), N-2- (4-(2-methylpropyl)phenyl)propionoyl-N’-(2’-chlorophenyl) thiourea (2) and N-2-(4-(2-methylpropyl)phenyl)propionoyl-N’-(3’,4’-dichlorophenyl) thiourea (3). Metal complexes (4-15) of (1-3) were synthesized by refluxing it with one equivalence salts of Co (ΙΙ), Ni(II), Pb(II) and Cu(I). Structures of all the synthesized thiourea ligands and their metal complexes were determined by FTIR and 1HNMR spectroscopy. Shift in stretching frequency in FTIR and resonance frequency in 1HNMR spectroscopic data suggested that the ligands and metal are coordinated to afford respective metal complexes M[L]n. The synthesized compounds were tested against urease enzyme and the results were compared with standard thiourea, as positive control. Most of the investigated compounds showed potential inhibitory activity against Jack bean urease. Compound 5 was found to be the most potent urease inhibitor with IC50 of 14.6 μΜ, whereas compounds 8, 11 and 12 possessed potent urease inhibition. The tested compounds can be taken as lead molecules for gastrointestinal ulcer therapy.

Abstract The present investigation deals with synthesis of new acid dyes from 4-amino-1-(4-sulfophenyl)-3-methyl-5-pyrazolone and phenol derivatives and their metal complexes (Cu (II) and Fe (II)). The phenol derivatives include 4-chlorophenol, 4-nitrophenol, 4-hydroxybenzene sulfonic acid, 2-nitrophenol-4-sulfonic acid, resorcinol and bisphenol A and bisphenol S. The newly synthesized dyes were applied to crust leather to assess their dyeing properties. The fastness properties of unmetallized dyes were less as compared to metal complexes due to the strong interaction of metals with leather protein. The structures of these dyes were also confirmed by UV, FTIR and NMR studies.

The present paper reports the synthesis of xanthene dyes derivatives from 4, 4'-oxydiphthalic anhydride and 1, 4, 5, 8-naphthalenetetracarboxylic dianhydride (3a-e and 6a-e) with different substituted phenols via Friedel-Crafts acylation reaction in the presence of an ammonium chloride catalyst. The structures of all newly synthesized derivatives were confirmed by the chromatographic, spectral and microelemental data. Dianhydride derivatives with 3-N', N'-dimethylaminophenol (3d and 6d) and resorcinol (3e and 6e) have been found to be highly fluorescent. Electrochemical study was done to determine band gap energy, LUMO and HOMO level energy. Band gap and LUMO energy levels were found to be lowest in xanthene derivatives 3c and 6c. Dyes 3d, 3e, 6d and 6e were found useful for differential staining of plant cells.

Synthesis of two series of 1,2- and 1,4-bis(thioureido)benzene derivatives was accomplished by the treatment of corresponding alkanoyl/aroyl chlorides with potassium thiocyanate in dry acetone to afford the respective isothiocyanates as intermediates. The latter were treated in situ with 1,2- and 1,4-diaminobenzene, respectively, to afford the title compounds in high yields. A total of sixteen new compounds are reported herein. The structures of the products were confirmed by spectroscopic techniques (IR, ¹H and 13C NMR, mass spectrometry), elemental analysis and in case of 1d, by X-ray diffraction technique. All the synthesized compounds were also subjected to antibacterial bioevaluation against ten different Gram-positive and Gram-negative bacterial strains using levofloxacin as the standard drug and were shown to possess promising activities.

Este trabalho relata uma síntese eficiente e regio-seletiva de algumas 2-aroylimino-3-aryl-thiazolidin-4-ones (2a-j) envolvendo a ciclização de 1-aroyl-3-aryl tio-uréias em meio básico com cloreto de cloroacetila em dioxana. As estruturas foram confirmadas por dados espectroscópicos, análises elementares e, em um caso (2j), por dados de difração de raios X tipo cristal único. Os compostos foram testados in vitro quanto à sua atividade antimicrobiana em relação a bactérias Gram positivas e Gram negativas. Os resultados revelaram uma atividade promissora desses compostos em relação aos microorganismos testados, comparando-se e, em alguns casos, até superando a atividade das drogas existentes.

An efficient, regioselective synthesis of some 2-aroylimino-3-aryl-thiazolidin-4-ones (2a-j) involving base-catalyzed cyclization of 1-aroyl-3-aryl thioureas with chloroacetyl chloride in dioxane is reported. The structures were confirmed by spectroscopic data, elemental analyses and in one case (2j) by single crystal X-ray diffraction data. Compounds (2a-j) were assayed in vitro for their antimicrobial activity against Gram positive and Gram negative bacteria and were found to exhibit promising activity towards the tested microorganisms, comparable to and in some cases better than those of the standard drugs.

Descreve-se a síntese da 8-hidróxi-6,7-dimetóxi-3-metil-3,4-diidroisocumarina (±) kigelina, um metabólito bioativo encontrado em Aspergillus terreus e Kigelia pinnata. O ácido 3,4,5-trimetóxi-homoftálico após tratamento com nidrido acético na presença de piridina, sob refluxo, forneceu o ácido 2,3,4-trimetóxi-6-(2-oxopropril)benzóico. Redução deste último, seguido de ciclodesidratação resultou na formação da 6,7,8-trimetóxi-3-metil-3,4-diidroisocumarina, que sofreu desmetilação regiosseletiva fornecendo a (±) kigelina.

A simple synthesis of racemic 8-hydroxy-6,7-dimethoxy-3-methyl-3,4-dihydroisocoumarin or kigelin, a metabolite of Aspergillus terreus and Kigelia pinnata, exhibiting several bioactivities, is described. 3,4,5-Trimethoxyhomophthalic acid was refluxed with acetic anhydride in dry pyridine to afford 2,3,4-trimethoxy-6-(2-oxopropyl)benzoic acid. Reduction of the latter followed by cyclodehydration yielded 6,7,8-trimethoxy-3-methyl-3,4-dihydroisocoumarin which on regioselective demethylation furnished the (±)-kigelin.