Glacial Acetic Acid Medium Research Articles

Definirea metodologiei spectrofotometrice UV-VIS de evaluare a concentrației malondialdehidei ca marker al calității în trasabilitatea a trei tipuri de carne

This research represents a follow-up of previous original investigation on the methodology for evaluating biochemical indicators in the quality of pork, beef and chicken in accordance with the technology of the slaughter stage. The UV-VIS spectrophotometric approach enables to determine the concentration of the malondialdehyde that in the investigation is defined as the freshness indicator of the fresh meat obtained after slaughter, which is a very important standard of traceability. In the proposed methodology, the investigated biochemical reaction consists in building the red chromogen with λ = 532 nm between thiobarbituric acid and malondialdehyde in the glacial acetic acid medium. A comparative analysis of the significant limit difference according to ANOVA was done between the meat samples kept in the thermostat and those placed in the refrigerator, and this confirmed the hypothesis of the rancidity mechanism in the raw material.

Synthesis, molecular docking and in vitro cytotoxicity studies of 3,5-dimetyl arylazo pyrazole derivatives

A new series of 3,5-dimethyl-arylazopyrazoles (3a-h) was synthesized by reacting various oxobutyrates (2) with 4-methoxy benzhydrazide (1) in glacial acetic acid medium. The oxobutyrates were prepared by diazotization of substituted anilines and subsequent condensation with acetyl acetone in the alcohol medium. The new compounds were elucidated on the basis of IR, 1H-NMR and mass spectral data and the compounds were screened for their in vitro cytotoxic activity using MDA-MB-231 and MCF-7 cell lines. Some of the tested compounds showed weak to moderate cytotoxic effects.

Nitration of Jharia basin coals, India: a study of structural modifications by XRD and FTIR techniques

Four coal samples from Jharia basin, India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical, petrographic and spatial structure of the organic mass by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. X-ray parameters of coal like interlayer spacing (d002), crystallite size (Lc), aroamticity (fa), average number of aromatic layers (Nc), and coal rank (I26/I20) have been determined using profile-fitting software. Considerable variation is observed in treated coals in comparison to the demineralized coals. The d002 values of treated coals have increased in both the media showing increase in disordering of organic moieties. A linear relationship has been observed between d002 values with the volatile matter of the coals. Similarly, the d002 values show linear relationship with Cdmf contents for demineralized as well as for the treated coals in both the media. The Lc and Nc values have decreased in treated coals corresponding to demineralized coals. The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity (fa) increases with increase in rank and shows a linear relationship with the vitrinite reflectance. The corresponding I26/I20 values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium. FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals (SMCs) in both the media, the corresponding bands at 1550–1490 and 1355–1315 cm−1 respectively. FTIR study confirms that nitration is the predominant phenomenon, though, oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs. In comparison to raw coals, the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.

Synthesis, Antibacterial and Antifungal Evlaution of Novel Pyrazoline Derivatives

A new series of chalcones (2a-j) were prepared by reacting substituted aldehydes and substituted ketones in alcohol medium in presence of NaOH. The chalcones underwent selective cyclization with guanicol hydrazide (1) in glacial acetic acid medium to yield the title compounds 1,3,5-trisubstituted pyrazolines (3a-j). The new compounds were characterized on the basis of 1H-NMR, IR and mass spectral data. All the newly synthesized compounds were evaluated for their in-vitro antibacterial and antifungal activities. Some of the tested compounds 3a and 3e showed good activity against bacterial strains and compounds 3d and 3h revealed good activity against fungal strains.
 Dhaka Univ. J. Pharm. Sci. 17(2): 221-226, 2018 (December)

COMPUTER PREDICTION AND SYNTHESIS OF NEW OXAZOLES BASED ON AN 8-THIOSUBSTITUTED 1,3,7-TRIMETHYLXANTHINE SKELETON

The synthesis of new oxazole derivatives was carried out under Davidson synthesis conditions from O-acylacyloins with an 8-thiosubstituted 1,3,7-trimethylxanthine skeleton and ammonium acetate in a 1:10 ratio in glacial acetic acid media. The starting O-acylacyloins were obtained as products from the interaction of the sodium salt of 2-(1,3,7-trimethyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-ylthio)acetic acid and a-haloketones. The structures of the new compounds were proven by microanalyses and spectral data. The PASS online web application was used to predict the biological activity spectra of the obtained derivatives and to determine the most promising biological effects for further experimental testing. Thus, it has been shown that the synthesized compounds are a promising class for the creation of substances with a wide range of biological activity. The substrate/metabolite specificity of the tested compounds was also predicted using SMP web-service. The studied compounds were considered to perform most probably with CYP2 substrate activity.

Synthesis and Antioxidant activity of novel Pyrazoline derivatives

Plan: A novel series of pyrazolines were synthesized through chalcones. The synthesized compounds were evaluated for various antioxidant activities. Preface: Pyrazolines belongs to five-membered nitrogen classes of compounds. Pyrazolines were reported with widespread chemotherapeutic activities. Methodology: A new series of Chalcones (2a-j) were prepared by reacting substituted aldehydes and ketones in alcohol medium in presence of NaOH. The chalcones (2a-j) undergoes selective cyclization with benzhydrazide (1) in glacial acetic acid medium to yield the title compounds 1, 3, 5-trisubstituted Pyrazolines (3a-j). The new compounds were assigned on the basis of 1H-NMR, IR and Mass spectral data. The newly synthesized compounds were screened for their In-Vitro antioxidant activity by DPPH, superoxide and nitric oxide methods. Outcome: Some of the tested compounds 3e, 3g, and 3f showed moderate activity when compared to the standard drug ascorbic acid.

Optimized steps in determination of malondialdehyde (MDA) standards on diagnostic of lipid peroxidation

Introduction: Lipid peroxidation, one of the known indices of oxidative stress, is documented in various diseases. Secondary oxidation products such as malondialdehyde (MDA) is commonly measured to observe lipid peroxidation. In this study, a spectrophotometric method was evaluated to measure thiobarbituric acid reactive substances (TBARS) with high sensitivity. This study was aimed to optimisation standard of MDA using tetraethoxypropane (TEP) 97% (FW=220.3). Methods: The method is based upon the reaction of malondialdehyde (MDA) and TBA in the glacial acetic acid medium. MDA is a known biomarker of oxidative status in a biological system. This research consists of two phases: first, making a stock of TEP, and the second phase was testing the concentration of TEP for finding the standard curve of MDA before used in diagnostic of lipid peroxidation. Results: Result showed the concentration 1,875-60 uM of TEP could form a precise standard curve. Conclusion: This concentration of TEP can be used as a reference as the standard of control in diagnostic of lipid peroxidation using TBARS method.

ELECTROPHYLIC HETEROCYCLIZATION OF 5-METHYL-6-TIOXOPYRAZOLO[3,4-d]PYRIMIDINE-4-ON

Derivatives of pyrazolo[3,4-d]pyrimidine have valuable biological activity. The structural fragment of pyrazolopyrimidines is widely used to develop new effective pharmaceuticals. A new promising direction in the construction of polycyclic systems based on pyrazolopyrimidine is the method of electrophilic intramolecular heterocyclicization.The halogenation of 5-methyl-6-thioxopyrazolo[3,4-d]pyrimidin-4-one was carried out in acetic acid medium at room temperature with twice the excess of halogen. It was found that halogenation (with bromine and iodine) of 5-methyl-6-thioxopirazolo[3,4-d]pyrimidin-4-one results the annelation of the thiazolinic cycle with the formation of linear polynuclear systems of a salt-like structure. 7-Halogenomethyl-7-methyl-1,4,6,7-tetrahydropyrazolo[3,4-d][1,3]thiazolo[3,2-a]pyrimidin-4-one was obtained via the action of sodium sulfite in the DMSO-water medium.To study the effect of the nature of the electrophilic reagent on the direction of the electrophilic intramolecular cyclization of 5-methyl-6-thioxopyrazolo[3,4-d]pyrimidin-4-one the p-methoxyphenyltetrachloride was used (tested). Electrophilic heterocyclization take place under similar conditions (room temperature, glacial acetic acid medium), with the formation of the tricyclic system with an exocyclic aryltellurium moiety – 7-(dichloro-(4-methoxyphenyl) telluromethyl)-7-methyl-1,4,6,7-tetrahydropyrazolo[3,4-d][1,3]thiazolo[3,2-a]pyrimidin-4-one. Thus, the direction of electrophilic intramolecular cyclization of 5-methyl-6-thioxopyrazolo[3,4-d]pyrimidine-4-one using as electrophilic agents of halogens (bromine, iodine) and p-methoxyphenyltetrachloride does not depend on the nature of the electrophile and takes place with the participation of the exocyclic sulfur atom in the second position of the pyrimidine and lead to the formation of a condensed system of linear structure – halogenomethyl or aryl telluromethyl derivatives of pyrazolo[3,4-d][1,3]thiazolo[3,2-a]pyrimidin-4-one. The composition and structure of all synthesized compounds were proved by elemental analysis and 1H-NMR spectra.

Synthesis and biological evaluation of novel imidazolinone derivatives

A new series of Oxazolones (2a-j) were prepared by reacting substituted aromatic aldehydes with N-acetylglycine in presence of anhydrous sodium acetate and acetic anhydride as the solvent medium. The respective Oxazolones (2a-j) were then treated with 4-Amino-1,2,4-triazole (1) in glacial acetic acid medium to yield the title compounds Imidazolinones (3a-j). All the newly synthesized compounds were evaluated for their In -Vitro antibacterial and antifungal activities. The new compounds were assigned on the basis of 1H-NMR, IR, Mass spectral data and elemental analysis.

Synthesis and in-vitro anti-inflammatory activity of novel pyrazoline derivatives

A new series of Chalcones (2a-j) were prepared by reacting 2-acetyl Pyrrole and substituted ketones in alcohol medium in presence of NaOH. The Chalcones undergoes selective cyclization with phenoxy acetic acid hydrazide (1) in glacial acetic acid medium to yield the title compounds 1,3,5-trisubstituted Pyrazolines (3a-j). The newly synthesized compounds were evaluated for their In-vitro anti-inflammatory activity by egg albumin denaturation and protein denaturation method. All the new compounds were established on the basis of 1H-NMR, IR and Mass spectral data. Some of the tested compounds 3a, 3f showed good anti-inflammatory activity when compared to the standard drug diclofenac sodium.

Synthesis, Antibacterial and Antifungal Evaluation of Novel Pyrazoline Derivatives

A novel series of Chalcones (2a-j) were prepared by reacting Furfuraldehyde and substituted ketones in alcohol medium in presence of NaOH. The Chalcones undergoes selective cyclization with Benzhydrazide (1) in glacial acetic acid medium to yield the title compounds 1,3,5-trisubstituted Pyrazolines (3a-j). All the newly synthesized compounds were evaluated for their In-Vitro antibacterial and antifungal activities. The new compounds were assigned on the basis of 1H-NMR, IR, Mass spectral data and elemental analysis. Some of the tested compounds showed potent activity against antifungal organism A.fumigatus.

A Simple Spectrophotometric Method for the Determination of Thiobarbituric Acid Reactive Substances in Fried Fast Foods.

A simple and highly sensitive spectrophotometric method was developed for the determination of thiobarbituric acid reactive substances (TBARS) as a marker for lipid peroxidation in fried fast foods. The method uses the reaction of malondialdehyde (MDA) and TBA in the glacial acetic acid medium. The method was precise, sensitive, and highly reproducible for quantitative determination of TBARS. The precision of extractions and analytical procedure was very high as compared to the reported methods. The method was used to determine the TBARS contents in the fried fast foods such as Shami kebab, samosa, fried bread, and potato chips. Shami kebab, samosa, and potato chips have higher amount of TBARS in glacial acetic acid-water extraction system than their corresponding pure glacial acetic acid and vice versa in fried bread samples. The method can successfully be used for the determination of TBARS in other food matrices, especially in quality control of food industries.

Synthesis and spectroscopic characterization of a new (aryl-SCN)n polymer: Polythiocyanatohydroquinone

In the present work we have demonstrated the first synthesis of the polythiocyanogen-like (aryl-SCN)n compound (polythiocyanatohydroquinone) from the initial 1,4-benzoquinone and NH4SCN reagents under the normal conditions in the glacial acetic acid medium. The synthesized amorphous polymer was characterized experimentally by the FT-IR and UV–vis spectroscopic methods accompanied with theoretical assignments by the density functional theory (DFT) and time-dependent DFT calculations. The transmission electron microscopy and the XRD pattern analysis were used to indicate the amorphous structure of the synthesized polymer. The DFT geometry optimization of a number of oligomers (n=4–8) permit us to predict the possible structure of polythiocyanatohydroquinone and to assign the observed bands in IR and UV–vis absorption spectra.It was found that the synthesized polythiocyanatohydroquinone powder has a complicated structure which can be represented as a branched polymer constructed from the mono- and doubly-SCN-substituted benzene-1,4-diol moieties. This new material demonstrates a good stabilizing effect in respect to colloidal solutions of Ag and Au nanoparticles. Additionally, polythiocyanatohydroquinone is predicted to be a promising candidate for creation of metal-containing composite materials. Its application as a framework for the Pt electrode closing is found very useful.

Synthesis and antimicrobial studies of furyl based new bispyrazolines linked via aliphatic chains

The symmetrical bisheterocycles built around varying lengths aliphatic linkers have been synthesized from the easy cyclization reactions of bischalcones with phenyl hydrazine by refluxing in dry EtOH and glacial acetic acid medium. The intermediates in turn were prepared in the good yields from O-alkylation of hydroxy substituted chalcone with suitable 1,ω-dibromoalkanes in the presence of anhydrous K2CO3, dry acetone and Bu4N+I− as PTC. The chalcone was obtained from the Claisen–Schmidt condensation reaction of p-hydroxyacetophenone with 2-furfuraldehyde. The structures of bischalcones and bispyrazolines were fully characterized by using various spectroscopic techniques including IR, 1H NMR, 13C NMR & Mass (ESI) and purity of these products were confirmed from their elemental analysis results. The newly prepared compounds were also screened for their antimicrobial activities against seven bacterial and five fungal strains by using serial tube dilution method. Some of the compounds exhibited significant activities against the tested microorganisms.

X-Ray Diffraction Studies of some Structurally Modified Indian Coals and their Correlation with Petrographic Parameters

In order to study the X-ray structural parameters, five coals have been chosen from different coal basins of India. These coals have been demineralized by standard HF + HCl treatment and treated with nitric acid in aqueous and glacial acetic acid media. X-ray diffraction (XRD) patterns of the samples are recorded using a slow step scan (2 s/step) over an angular range 2θ ∼ 10-90°. TOPAS software has been used to determine the structural parameters like interlayer spacing ( d 002 ), crystallite size ( L c ), aromaticity ( f a ) and average number of aromatic layers ( N c ). The structural parameters have been correlated with chemical as well as petrographic parameters of coals. Mean random reflectance (MR r ) of the studied coals varies between 0.44% and 0.54% and the vitrinite, liptinite and inertinite contents vary between 17.8% and 66.4%, 9.2% and 20.3% and 20.7% and 62.9% respectively. Nitration in both the media has increased d 002 values. This study also shows that d 002 and fa values are dependent on the rank of the coal, rather than only the carbon content ( C dmf , dry mineral free basis). XRD rank parameter values have been directly correlated with the petrographic rank parameters. Nitration in both the media has induced similar kind of effect on individual macerals. Behaviour of the macerals to chemical treatment is also reported in this study.

A single stage process for the preparation of cycotetramethylene tetranitrmine

A single stage process for the preparation of cyclotetrmethlene tetranitramine (HMX)has been developed. The ingredients (i) Hexamine in glacial acetic acid, (ii) Ammonium nitrate in nitric acid and (iii)acetic anhydride were simultaneously added to glacial acetic acid medium maintained at 45-48 with stirring. The crude yield of the product per 100 gm. of hexamine used is 120 gm having the melting point 265-266C. Purified from acetone the substance melts at 272-275 and passes standard vacuum stability and impact sensitivity tests.

Sensitive Spectrophotometric Method for Determination of Trace Aluminium in Water Samples by Morin

The chromogenic reaction of Al (III) with morin was studied in the presence of cationic surfactant cetyltrimethylammonium bromide(CTMAB), Al (III) was capable of reacting with morin to form a stable yellow complex in 0.17 mol l-1 glacial acetic acid media. The complex had a 1∶2 molar ratio for Al (III) and morin . In the presence of cationic surfactant CTMAB, the sensitivity of chromogenic reaction was largely improved. At the maximum absorption wavelength of 425nm, the apparent molar absorptivity was 1. 59×105l·mol - 1·cm- 1 .Beer′s law was obeyed in the range of 0 to 8μg/ 25ml Al (III) . The method has been applied successfully to the determination of trace amount of aluminium in tap and river water samples.

Ozonization of humic acids in brown coal oxidized in situ

The effect of the ozonization of humic acids in chloroform and glacial acetic acid media on the yield and component composition of the resulting products was studied. The high efficiency of ozonization in acetic acid was found. Water-soluble low-molecular-weight substances were predominant among the ozonization products.

Investigation of the anodic acetoxylation of p-methylanisole ( p-MA) in glacial acetic acid medium using graphite (sp 2) and BDD (sp 3) electrodes

The electrochemical investigation of carbon fiber (CF) and boron-doped diamond (BDD) ultramicroelectrodes (UME) in glacial acetic acid medium has shown that the overpotential for acetate oxidation is higher on BDD than on CF. Preparative electrolyses have revealed that the main anodic products correspond to the Kolbe reaction. Beside these products small amounts of methane and methyl acetate are formed in different amounts depending on electrode material. This difference has been attributed to the different adsorption properties of CF (sp 2) and BDD (sp 3). Electrochemical measurements of p-MA in glacial acetic acid media have shown that p-MA is firstly oxidized to the corresponding radical cation. This intermediate, formed at both CF and BDD electrode, can either be attacked by the AcO − nucleophile leading to acetoxylated product or undergo dimerization ending up in polymeric material. The obtained results show clearly that on graphite acetoxylation is favored contrary to BDD where the dimerization step also takes place. Selectivity up to 93% monoacetoxylated product can be achieved on graphite for more than 90% conversion of p-MA using a bipolar capillary gap cell.

Synthesis of [2-aryl-6-oxo-6H-chromeno[6,7-d]oxazol-8-yl]-acetic acid ethyl esters

A number of coumarino[6,7-d]oxazoles (nitrogen analogs of psoralens) have been synthesized from (7-hydroxy-2-oxo-2H-chromen-4-yl) acetic acid ethyl ester 1. The synthetic route began with the nitration of 1 with nitric acid in acetic acid to give (6-nitro-7-hydroxy-2-oxo-2H-chromen-4-yl) acetic acid ethyl ester 2; (3,6-dinitro-7-hydroxy-2-oxo-2H-chromen-4-yl) acetic acid ethyl ester 3 and (3,6,8-trinitro-7-hydroxy-2-oxo-2H-chromen-4-yl) acetic acid ethyl ester 4. The reduction of 2 was accomplished with tin(II) chloride, tin, and concentrated hydrochloric acid in ethanol giving (6-amino-7-hydroxy-2-oxo-2H-chromen-4-yl) acetic acid ethyl ester 5. After the condensation of aminocoumarin 5 with aromatic aldehyde in glacial acetic acid medium, followed the dehydrocyclization to coumarino[6,7-d]oxazoles 7a-k. The intermediate Schiff's bases 6a-k have been obtained from 5 with aromatic aldehyde in ethanol. Antibacterial and antifungal activities of the compounds have been evaluated.