Microwave-assisted synthesis and characterization of novel metal-free and metallophthalocyanines containing four 14-membered tetraaza macrocycles

The novel tetrasubstituted metal-free phthalocyanine (6) and metallophthalocyanines (7, 8) bearing four 14-membered tetraaza macrocycles moieties on peripheral positions have been synthesized by cyclotetramerization reaction of phthalonitrile derivative (5) in a multi-step reaction sequence. The new compounds were characterized by a combination of IR, 1H NMR, 13C NMR, UV-vis, elemental analysis and MS spectral data. © 2007 Elsevier B.V. All rights reserved.Karadeniz Teknik Üniversitesi: 2002.111.002.6This study was supported by the Research Fund of Karadeniz Technical University, Project No: 2002.111.002.6 (Trabzon–Turkey)

Microwave-assisted synthesis of novel 2,4-dihydro-5-[4-(trifluoromethyl) phenyl]-3h-1,2,4-triazol-3-ones and potentiometric determination of their pKa in nonaqueous solvents

The novel 4-amino- or 4-aryl-substituted 2,4-dihydro-5-[(4-trifluoromethyl) phenyl]-3H-1,2,4-triazol-3-ones 3a-3g were synthesized by reaction of N-(ethoxycarbonyl)-4-(trifluoromethyl)benzenehydrazonic acid ethyl ester (2) and primary amines or hydrazine by microwave irradiation. Compounds 3a-3g were potentiometrically titrated with tetrabutylammonium hydroxide (Bu 4NOH) in four nonaqueous solvents, i.e., iPrOH, tBuOH, MeCN, and N,N-dimethylformamide (DMF). Also half-neutralization potential values and the corresponding pKa values were determined in all cases. © 2010 Verlag Helvetica Chimica Acta AG, Zürich, Switzerland

Studies on the protonation constants of some triazoles in ethanol-water mixtures

Several studies, involving the formation and investigation of biological activities of some triazoles derivatives. These derivatives have weak acidic properties. To gain more information about the effect of solvent on triazoles, the stoichiometric protonation constants of 17 triazoles (3 series) in ethanol-water mixtures were determined at an ionic strength of 0.10 M NaCl and at 25.0 ± 0.1°C under nitrogen atmosphere. A Potentiometrie method was used and the calculation was carried out using the PKAS computer program. The corresponding pKa values of these triazoles were determined in ethanol-water mixtures mixtures. Thus, the effects of solvent and molecular structure upon acidity were investigated. The logarithm of the protonation constants of the triazoles decreased linearly with increasing ethanol content. The variation of these constants is discussed on the basis of specific solute-solvent interactions

Rapid and efficient microwave-assisted synthesis of some new triazol-3-one derivatives

A growing body of literature has shown the effectiveness of using microwaves in chemical reactions. The aim of this study is to demonstrate a rapid and highly efficient synthesis of some new triazol-3-ones via microwave heating using a monomode microwave. Compared with the thermal process, the microwave heating induces a dramatic reduction of the reaction time and improvement of the yields. In this study, rapid N-benzylation and N-acetylation of triazol-3-ones were achieved by microwave irradiation method for the first time. The newly synthesized compounds showed moderate antimicrobial activity against the standard bacterial and fungal organisms tested. © 2013 HeteroCorporation

Microwave-assisted synthesis of some 1, 2, 4-triazol-3-ones and potentiometric determination of their pKa in amfiprotic and dipolar aprotic-water mixtures

The novel 5-alkyl(aryl)-4-(aryl)-2, 4-dihydro-3H-1, 2, 4-triazol-3-ones (1-12) were synthesized by reaction of (N?-ethoxycarbonyl)-4-alkyl(aryl)hydrazonic acid ethyl ester with primary amines by microwave irradiation. Stoichiometric protonation constants of 1-12 were determined potentiometrically in 50% (v/v) amfiprotic (ethanol and methanol) and dipolar aprotic (dioxan)-water mixtures at 25°C with an ionic strength of 0.10 M. The calculation of the stoichiometric protonation constants was carried out using a PKAS computer program. The effects of solvents composition on the stoichiometric protonation constants are discussed

Synthesis of novel triazol compounds containing isatin as potential antibacterial and antifungal agents by microwave and conventional methods

Microwave irradiation has been used to accelerate the conversion of isatin (1a) and 5-nitroisatin (1b) into their Schiff bases 3-[5?-aryl(alkyl)- 2?,4?-dihydro-1?,2?,4?-triazol-3?-on- 4?-yl]iminoisatin (3a-g) and 3-[5?-aryl(alkyl)-2?,4?- dihydro-1?,2?,4?-triazol-3?-on-4?-yl] imino-5-nitroisatin (4a-g), respectively. Reaction was achieved by microwave-induced technique, which reduced the reaction time drastically and improved the yield when compared to conventional heating. The newly synthesised bases showed moderate antimicrobial activity against the standard bacterial and fungal organisms tested

Determination of the protonation constants of triazole derivatives in non-aqueous solvents

Different 17 triazole derivatives were titrated with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, rert-butyl alcohol, N,N-dimethylformamide and acetonitrile), using Potentiometric method. The half neutralization potential values and the corresponding pKa values were determined for all cases

Microwave-assisted and conventional synthesis of new phthalocyanines containing 4-(p-fluorophenyl)-3-methyl-4,5-dihydro-1H-1,2,4-triazol-5-one moieties

New metal-free and metal (Zn, Ni, Cu and Co) phthalocyanines containing 4-(p-fluorophenyl)-3-methyl-4,5-dihydro-1H-1,2,4-triazol-5-one moiety have been prepared from 1-(3,4-dicyanophenyl)-4-(p-fluorophenyl)-3-methyl-4,5-dihydro-1H-1,2,4-triazol-5-one by both conventional and microwave-assisted methods. All of these compounds are soluble in CHCl3, DMF and DMSO. The new compounds have been characterized by elemental analysis, IR, NMR, UV-Vis spectroscopies. The crystal structures of compounds I and II were also determined by the single crystal diffraction technique. © 2007 Elsevier B.V. All rights reserved.This work was supported by the research fund of the Karadeniz Technical University of Trabzon