Haydar Yüksek

Synthesis, Acidity and Antioxidant Properties of Some Novel 3,4-disubstituted-4,5-dihydro-1H-1,2,4-triazol-5-one Derivatives

3-Alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2a-g reacted with4-diethylaminobenzaldehyde to afford the corresponding 3-alkyl(aryl)-4-(4-diethyl-aminobenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3a-g. The acetylation reactions of compounds 3a-e were investigated and compounds 4a-e were thus obtained. The new compounds were characterized using IR, 1H-NMR, 13C-NMR, UV and MS spectral data. In addition, the newly synthesized compounds 3a-g were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropyl alcohol, tert-butyl alcohol, acetone and N,N-dimethylformamide (DMF), and the half-neutralization potential values and the corresponding pKa values were determined for all cases. Moreover, 3 and 4 type compounds were also screened for their antioxidant activities.

Synthesis and determination of pKa values of some new 3,4-disubstituted-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives in non-aqueous solvents.

3-Alkyl(Aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) reacted with 2-furoyl chloride and thiophene-2-carbonyl chloride to afford the corresponding 3- alkyl(aryl)-4-(2-furoylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (3) and 3-alkyl(aryl)- 4-(2-thienylcarbonylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (4), respectively. The new compounds synthesized were characterized by using IR, 1H-NMR, 13C-NMR and UV spectral data together with elemental analysis. In addition, to investigate the effects of solvents and molecular structure upon acidity, compounds 3 and 4 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, N,N-dimethylformamide and acetonitrile). The half-neutralization potential values and the corresponding pKa values were determined for all cases.

A Study on 4-Acylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones

Five novel 3-alkyl-4-phenylacetylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with phenylacetyl chloride and characterized by elemental analyses and IR, 1HNMR, 13C-NMR and UV spectral data. The newly synthesized compounds 2 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide, and the half-neutralization potential values and the corresponding pKa values were determined for all cases. In addition, these new compounds and five recently reported 3-alkyl-4-(pmethoxybenzoylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (3) were screened for their antioxidant activities.

Synthesis, In Vitro Antimicrobial and Antioxidant Activities of Some New 4,5-Dihydro-1H-1,2,4-triazol-5-one Derivatives

A series of compounds derived from 4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐one were synthesized and characterized by spectral data. The 12 new compounds were analyzed for their potential in vitro antioxidant activities by three different methods. Compound 4f showed the best activity for the iron binding. In addition, the compounds 4 were titrated potentiometrically with tetrabutylammonium hydroxide in non‐aqueous solvents. The RP‐HPLC capacity factors (k′) of the series were also determined on a C18 column, with methanol/water as the mobile phase. The correlation between log k′ with the percentage of methanol in the mobile phase was used for the determination of the log kw values for these compounds. The antimicrobial activities of these compounds were also screened against bacteria and yeast.

Synthesis and In Vitro Antioxidant Evaluation of Some Novel 4, 5-Dihydro-1H, 2, 4-triazol-5-one Derivatives

In this study, thirteen novel 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives were synthesized and characterized by elemental analyses and IR, 1H NMR,13C NMR and UV spectral data. The synthesized compounds were analyzed for their in vitro potential antioxidant activities in three different methods. Those antioxidant activities were compared to standard antioxidants such as BHA, BHT and α-tocopherol. The data reveal that the compounds demonstrate a marked capacity for iron binding, especially 5a and 7c In addition to this, the compounds 4 were titrated potentiometrically with TBAH in non-aqueous solvents because of the weak acidic properties of 4,5-dihydro-1H-1,2,4-triazol-5-one ring N-H group.

Synthesis and Non-Aqueous Medium Titrations of Some New 4-Benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one Derivatives

The synthesis of 3-alkyl(aryl)-4-(3-ethoxy-4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3 from the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2 with 3-ethoxy-4-hydroxybenzaldehyde is described. The acetylation and methylation reactions of the compounds 3 giving compounds of type 4 and 5, respectively, were investigated. The newly synthesized compounds were characterized using elemental analyses and IR, 1H-NMR, 13C-NMR and UV spectral data. In addition, to investigate the effects of solvents and molecular structure upon acidity, compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide). The half-neutralization potential values and the corresponding pKa values were determined for all cases.

In Virto Antioxidant Activities of New 4,5-Dihydro-1H,2,4-triazol-5-ones having Thiophene Ring with their Acidic Properties

Seven new 3-alkyl(aryl)-4-(2-thienymethylenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with thiophene-2-carbaldehyde. In addition, N-acetyl derivatives of compounds 2d-2g were also prepared. The structures of eleven new compounds synthesized were determined by elemental analysis as well as IR, NMR and UV spectral data. In addition, compounds 2a-g and 3a, 3b, 3d-f were also screened for their antioxidant activities and 2a-g were potentiometrically titrated with tetrabutylammonium hydroxide (TBAH) in four nonaqueous solvents (isopropyl alcohol, t-butyl alcohol, acetonitrile and N,N-dimethyl formamide). Also half-neutralization potential values and the corresponding pKa values were determined in all cases.

Synthesis and In Vitro Antioxidant Evaluation of New 1,3,5-Tri-{2-methoxy-4-[(4,5-dihydro-1-1,2,4-triazol-5-on-4-yl)-azomethine]-phenoxycarbonyl}-Benzene Derivatives

Nine new 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives were synthesized and characterized by elemental analyses and IR, 1H-NMR, 13C-NMR and UV spectral data. The synthesized compounds were analyzed for their in vitro potential antioxidant activities in three different methods. Those antioxidant activities were compared to standard antioxidants such as BHA, BHT and 𝛼-tocopherol. Compounds 4e, 5a and 5d showed best activity for iron binding. In addition, the compounds 4 were titrated potentiometrically with tetrabutylammonium hydroxide (TBAH) in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetone and N,N-dimethyl formamide). Thus, the half-neutralization potential values and the corresponding p𝐾a values were determined in all cases.

B3LYP ve HF Temel Setleri Kullanılarak Bazı 3-Alkil-4-(2-asetoksi-3-metoksibenzilidenamino)-4,5-dihidro-1H-1,2,4-triazol-5-on Bileşiklerinin Deneysel ve Teorik Özelliklerinin İncelenmesi / The Investigation of Experimental and Theoretical Properties of Some 3-Alkyl-4-(2-acetoxy-3-methoxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-one Using B3LYP and HF Basis Sets

Bu calismada, bes adet 3-alkil-4-(2-asetoksi-3-metoksibenzilidenamino)-4,5-dihidro-1 H -1,2,4-triazol-5-on bilesiginin teorik ozellikleri B3LYP/6-311G(d,p) ve HF/6-311G(d,p) temel setleri kullanilarak incelenmistir. Ilk olarak, her bir molekul B3LYP/6-311G(d,p) ve HF/6-311G(d,p) temel setleri kullanilarak optimize edilmistir. Gaussian G09W paket programi kullanilarak GIAO metoduna gore molekullerin 1 H-NMR ve 13 C-NMR isotropik kayma degerleri hesaplanmistir. IR verilerinin belirlenmesinde veda4f programi kullanilmistir. Incelenen her bir molekulun iki farkli temel set ile IR (infrared) titresim frekans degerleri gaz fazinda hesaplanmis ve uygun uyum faktorleri ile carpilmistir. Elde edilen bu degerlere gore molekullerin infrared spektrumlari cizilmistir. Bilesiklerin bag uzunluklari, mulliken yukleri, en yuksek dolu molekuler orbital enerjisi (HOMO) ve en dusuk bos molekuler orbital enerjisi (LUMO), dipol moment degerleri de hesaplanmistir. In this study, theoretical properties of five 3-alkyl-4-(2-aceoxy-3-methoxybenzylidenamino)-4,5- dihydro-1 H -1,2,4-triazol-5-ones were investigated using B3LYP and HF basis sets. Firstly, each molecule were optimized by using the B3LYP/6-311G(d,p) and HF/6-311G(d,p) basis sets. 1 H-NMR and 13 C-NMR isotropic shift values of molecules were calculated by the method of GIAO using the program package Gaussian G09W. The veda4f program was used in defining IR data. IR (infrared) vibrational frequencie values with two different basis set investigated of each molecule was calculated in gas phase and are multiplied by appropriate adjustment factors. Infrared spectra of molecules according to obtained these values are formed. Also, bond lengths, mulliken charges, the highest occupied molecular orbital (HOMO) energys and the lowest unoccupied molecular orbital (LUMO) energys, dipole moment values of these compounds were calculated.

Synthesis and acidic properties of new 1-phenylacetyl-3-ethyl-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-one

It is known that 1,2,4-triazole and 4,5-dihydro-1H-1,2,4-triazol-5-one rings have weak acidic properties, so some 1,2,4-triazole and 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives were titrated potentiometrically with tetrabutylammonium hydroxide in non-aqueous solvents, and the pKa values of the compounds were determined [1,2,3].[...]