Mehmet Yilmaz

Synthesis and biological activity studies of furan derivatives

The organic compounds, 4-Ethyl-2,5,5-triphenyl-4,5-dihydrofuran-3-carbonitrile; 2,4,5-Triphenyl-5-propyl-4,5-dihydrofuran-3-carbonitrile; 4-Ethyl-5,5-diphenyl-2-thien-2-yl-4,5-dihydrofuran-3-carbonitrile; 2-(1-Benzofuran-2-yl-)-5-propyl-4,5-diphenyl-4,5-dihydrofuran-3-carbonitrile; 4-Ethyl-5,5-diphenyl-4,5-dihydro-2,2’-bifuran-3-carbonitrile, were synthesized and purified through column chromatography and preparative TLC. All compounds were characterized by IR, 1H, 13C NMR, MS, and microanalysis. The in vitro antibacterial and antifungal activities of these compounds were investigated against some bacteria and fungi. The antibacterial and antifungal activities were measured by using the disc-diffusion method against gram-positive bacteria, i.e., Staphylococcus aureus ATCC 25923, Staphylococcus enteritidis ATCC1376, Psydomamonas aeruginosa ATCC 29212, Bacillus subtilis RSKK 244, Bacillus megaterium gram-negative bacteria Escherichia coli ATCC 27853, Listeria monocytogenes ATCC 7644, and as fungus Micrococcus Luteus NRRLB was used. All compounds in this study showed activity against test bacteria. Their antibiogram tests showed better results than some known antibiotics.

SYNTHESIS OF BENZOFURAN DERIVATIVES USING MANGANESE (III) ACETATE MEDIATED ADDITION OF β-DICARBONYL COMPOUNDS TO ALKYNE AND ALKENES – A COMPARATIVE STUDY

β-Dicarbonyl compounds were easily oxidized with manganese (III) acetate in acetic acid to form the corresponding α-carboradicals, which attacked alkyne and alkenes to give furan derivatives in good yield.

Synthesis of 2,3‐Dihydro‐4H‐furo[3,2‐c] chromen‐4‐ones and 2,3‐Dihydronaphtho[2,3‐b]furan‐4,9‐diones by the Radical Cyclizations of Hydroxyenones with Electron-Rich Alkenes using Manganese(III) Acetate

Abstract We have obtained dihydrofurans 3a–j in the radical cyclization of 4‐hydroxycoumarin 1a and 2‐hydroxy‐1,4‐naphtoquinone 1b with electron rich alkenes 2a–i by manganese(III) acetate. Methods A and B, which have different molar ratios were studied comparatively in these reactions, and we observed that method B (molar ratio 2:1:3) gave the best results. Treatment of 4‐hydroxycoumarin 1a and electron rich alkenes 2a–e gave 2,3‐dihydro‐4H‐furo[3,2‐c]chromen‐4‐ones 3a–e in 36–86% yields by the method B. Under the same conditions, the reactions of 2‐hydroxy‐1,4‐naphtaquinone 1b with conjugated alkenes 2b and 2f–i afforded 2,3‐dihydronaphtho[2,3‐b]furan‐4,9‐diones 3f–j in an excellent yields.

Free Radical Cyclization of 1,3-Dicarbonyl Compounds Mediated by Manganese(III) Acetate with Alkynes and Synthesis of Tetrahydrobenzofurans, Naphthalene, and Trifluoroacetyl Substituted Aromatic Compounds.

Abstract Furan derivatives were obtained from radical cyclizations of 1,3‐dicarbonyl compounds mediated by Mn(OAc)3 with phenyl acetylene 2a (14–66% yields). Naphthalene derivates 4a and 4b were produced in the treatments with 2a. In addition to these, trifluoroacetyl substituted naphthalene 4c, benzofuran 4d, and benzothien 4e were obtained in the reactions of trifluoromethyl‐1,3‐dicarbonyls (1 g–i) with 2a.

REGIOSELECTIVE SYNTHESIS OF 5-CARBAMOYL-DIHYDROFURANS MEDIATED MANGANESE (III) ACETATE IN ACETIC ACID

β-Dicarbonyl compounds were easily oxidised with manganese (III) acetate in acetic acid, to form the corresponding α-carboradicals, which attacked alkenes at reflux temperature to give new 5-carbamoyl-dihydrofurans in good yield.

Synthesis of dihydrofuro- and C-alkenylated naphthoquinones catalyzed by manganese(III) acetate

The easily synthesis of dihydrofuronaphthoquinones and C-alkenylated naphthoquinones has been investigated through the radical oxidative cyclization of 2-hydroxy-1,4-naphthoquinones and thiophene or furan substituted alkenes catalyzed by manganese(III) acetate. The corresponding heteroaryl substituted dihydrofurans and naphthoquinones have been isolated in good yields.

Transmuted two-parameter Lindley distribution

ABSTRACT In this study, we propose a new distribution using the quadratic rank transmutation map named as transmuted two-parameter Lindley distribution (TTLD). This distribution is more flexible than the two-parameter Lindley distribution (TLD). The properties of the TTLD are examined, and estimation methods for the parameters of this distribution are discussed. The usefulness of the TTLD is demonstrated on some real data.

Hazard Rate Properties of Systems with Two Components

In this article, we study the hazard rate ordering of lifetimes of two-component systems (series and parallel) by considering some bivariate distributions for the joint distribution of component lifetimes. Such that, we aim to investigate the lifetimes of systems with stochastically dependent and with stochastically independent components, the lifetimes of the components, and a stochastic ordering relation between these lifetimes. In addition to these, the mononotonicity of the hazard rates of the parallel and the series systems for the bivariate Farlie–Gumbel–Morgenstern (FGM) family is studied.

Synthesis of new 2,5-di(thiophen-2-yl)furan-3-carbonitrile derivatives and investigation of the electrochromic properties of homopolymers and co-polymers with EDOT

New 2,5-di(thiophen-2-yl)furan-3-carbonitriles as thiophene–furan–thiophene type monomers (2a and 2b) were synthesized by the oxidation of 2,5-di(thiophen-2-yl)-4,5-dihydrofuran-3-carbonitriles which were prepared by the reaction of 3-oxopropanenitriles with alkenes mediated with manganese(III) acetate using DDQ (2,3-dichloro-5,6-dicyano-p-benzoquinone). The monomers and their copolymers with EDOT were electrochemically polymerized in acetonitrile (AN)/LiClO4. The electrochemical, spectroelectrochemical and morphological properties of the resulting polymer and copolymer films were investigated by cyclic voltammetry, UV-visible spectroscopy and atomic force microscopy. Observed differences in cyclic voltammetry, UV-vis spectroscopy and neutral state absorption (π–π* transition) have been accepted as evidence for the copolymerization. Copolymer films have distinct electrochromic properties according to superposition of the contained polymer properties. In addition the dissolution problem thats causing the instability of poly2b has been fixed with copolymerization. Switch time measurements showed that copolymer films are candidates for ECD applications due to their stability, fast response time and good optical contrast.

A Classical Approach to Modeling of Coal Mine Data

Data sets such as the occurrence time of random events or the lifetime of a certain product (or a system) are modelled by compound or mixture distributions especially in the last years. This situation is led to encounter proposal of more complex distribution models in the literature. One of the data set made a model proposal by in this way is coal mine data set. In this study, Two Component Mixed Exponential Distribution (2MED) model had more easier interpretation on this data set is used and compared with the other study results. Also, the extended coal mine data set with 191 observations is modelled by 2MED and the results are given.