Asian Journal of Chemistry

995-1000

Authors: Raji Thomas*, and Pushpa Pardasani

Penta and tetra coordinated germanium complexes have been synthesized from N,N’-bis(2-pyridyl)pyridine-2,6-dicarboxamide (H2L) and N-(pyridine-2-yl)picolinamide (HL1) with dialkyl/aryl and trialkyl/aryl germanium halides in 1:1 molar ratios. The molecular structures and electronic properties of complexes were well analyzed by GAUSSIAN 03 suit of programs. The transannular bonding observed in penta coordinated complexes have been well established by natural bond orbital, Wiberg bond index and molecular electrostatic potential analysis.

1007-1014

Authors: A. Akila, P. Sakthivel and S. Ponnuswamy*

A few N5-substituted (1) and N1,N5-disubstituted tetrahydro-1,5-benzodiazepin-2-ones (2-8) viz. N5-chloroacetyl-, N5-formyl-, N5-dichloro-acetyl-, N1,N5-diethoxycarbonyl-, N1,N5-bischloroacetyl-, N5-piperazinoacetyl- and N5-morpholinoacetyltetrahydro-1,5-benzodiazepin-2-ones have been synthesized. The characterization and conformational analysis of these compounds 2-8 have been carried out using IR and 1H, 13C, DEPT & 2D (COSY & HSQC) NMR spectral techniques. The coupling constants for compounds 3-6 were determined by irradiating the C4-methyl doublet. The appearance of major and minor conformers has been found in the case of benzodiazepin-2-ones (3 and 6) and the spectral data confirm the equilibrium due to ring inversion over the N-C=O rotation. The spectral data and the extracted coupling constant values revealed that the substituted tetrahydro-1,5- benzodiazepin-2-ones (2-8) prefer to adopt boat conformation. The antimicrobial activity of compounds 1-8 has also been evaluated.

1026-1032

Authors: N.H. Albariman*, S.F. Sabran, N.W. Othman, N. Ishak, A.S. Dheyab and N. Anjur

Crops are being damaged by several plant pests. Several strategies have been developed to restrict the damage of cultivated plants by using synthetic pesticides and repellants. However, the use to control these insects is highly discouraged because of their risks on humans. Therefore, several alternatives have been developed from plant extracts to protect crops from plant pests. Accordingly, this review focuses on outlining the insecticidal and repellant activities of Southeast Asia plants towards insect pests. Several extracts of plants from Southeast Asia were investigated to explore their insecticidal and repellant activities. Azadiracha indica (neem) and Piper species were highly considered for their insecticidal and repellant activities compared to other plants. This review also addressed the investigation on extracts of other plant species that were reported to exert insecticidal and repellant activities. Most of the conducted studies have been still in the primarily stage of investigation, lacking a focus on the insecticidal and repellant spectrum and the identification of the active constituents which are responsible for the insecticidal and repellant activity.

1039-1042

Authors: Mridula Gupta* and Sheela M. Valecha

A new series of heterocyclic Schiff bases were prepared from condensation of 1-phenyl-3-methyl-4- acetyl/benzoyl-pyrazolone with 4,4′-diaminodiphenylmethane and 4,4′-diaminodiphenyl ether, resulting in the formation of four novel Schiff base ligands. These ligands were then treated with ethanolic solution of PdCl2, to form corresponding palladium(II) complexes. These complexes were characterized by elemental analysis, IR, 1H NMR, TGA, magnetic susceptibility measurements and UV-visible absorption spectroscopy. All the Pd(II) complexes were found to have one coordinated water molecule. Schiff base ligands chelated with the metal atom through two donor sites N and O of azomethine (-C=N-) and phenolic (-OH) groups, respectively.

1048-1058

Authors: R. Mini, T. Joselin Beaula, P. Muthuraja and V. Bena Jothy*

4-Methyl-(2-nitrobenzylidene)aniline (MNBA) was grown and its structural as well as spectral analyses (FT-IR, FT-Raman, UV and NMR) using experimental and DFT computations were performed to understand its biological applications. Stability of molecule, charge delocalization, charge analysis and charge transfer interactions had been explored to examine the structural analysis. Docking studies also suggested that 4-methyl-(2-nitrobenzylidene)aniline exhibit antibacterial activity. Supramolecular assembly of 4-methyl-(2-nitrobenzylidene)aniline molecule was interceded by C-H···O hydrogen bonds and nitro···π(arene) interactions

1064-1068

Authors: Kasani Kumaraswamy, Hima Bindu Gandham, Rudrakshula J.D. Prasad, B. Amarender Reddy, Muralidharan Kaliyaperumal and Chidananda Swamy Rumalla*

Valsartan is used to treat high blood pressure, heart failure and diabetic kidney disease. It was subjected to forced degradation under acidic, basic and peroxide mediated oxidation. The forced degradation was performed according to ICH guidelines Q1A(R2)−Stability Testing of New Drug Substances and Products. The drug was inert under peroxide mediated hydrolysis, two degradants (DP-Val-1, DP-Val-2) were formed in base hydrolysis and one degradant (DP-Val-3) was formed in acid hydrolysis. These degradants were initially identified through LC-MS and isolated by mass mediated purification system. DP-Val-1 and DP-Val-3 are already reported but their structures were not confirmed by 2D NMR studies. DP-Val-2 is novel degradant and its structure has been elucidated by substantial analysis of high resolution mass spectrometry and 1D, 2D NMR spectroscopy. DP-Val-1 consists of a mixture of rotamers and this hypothesis was confirmed by variable temperature NMR (VT-NMR). A stability indicating RP-UPLC method was developed and validated for assay determination valsartan API drug. A valsartan UPLC method was validated on Acquity BEH C-18 2.1 × 100 mm, 1.7 μm column with shorter runtime of 6 min and the method was validated as per regulatory guidelines in terms of specificity, accuracy, linearity, precision, limit of detection and limit of quantitation.

1075-1081

Authors: M. Bencela* and S. Sudha Kumari

A new series of [M(L)Y]X·nH2O (M = Co(II) and Cu(II), where Y = H2O, X= NO3 –, n = 3), M = Ni(II), where Y = H2O, X = NO3 –, n = 2) complexes with new Schiff base ligand (L) were synthesized by the condensation of citral and L-histidine. The ligand and its M(II) complexes were characterized based on elemental analysis, spectroscopic studies like FT-IR, electronic, 1H NMR, 13C NMR, ESR data, also accompanied with thermal studies, magnetic susceptibility and molar conductance measurements. In the light of these results, distorted square planar geometry were proposed for the M(II) complexes in which the M(II) centres are present in NNO coordination sphere. To evaluate the biological properties of the Schiff base ligand ( L) and its metal complexes, they were screened for their antibacterial and antifungal activities and the results indicate that the complexes exhibit the significant activity.

1087-1090

Authors: Mahmoud Kamal, Ahmad Al-Sheikh Kaddour, Mohamad Haroun and Mofeed Yassin

In this study, efforts were made to isolate phtochemicals from European mistletoe (Viscum album L.) using hot (Soxhlet) and cold (magnetic rotation) extraction methods. The dried Viscum album L. (10 g) were extracted exhaustively by Soxhlet with methanol and dichloroethane solvents. Subsequently, 1 μL of sample was utilized for GC/MS analysis, which exhibited 50 peaks of phytoconstituents in the range of 0.12-22.04%. The highest flavonoids content was determined using quercetin calibration curve having a value of 62.26 mg QE/g dry weight.

1101-1108

Authors: Krishna Kumar Yadav, Anil Kumar, Mohd Kashif Aziz, Rafat Saba, Ashish Rajak and Shekhar Srivastava*

Novel thiazolidine-2,4-dione (TZD) based pyrimidine derivatives have been synthesized by Knoevenagel condensation reaction between thiazolidine-2,4-dione and amino pyrimidinyl aliphatic aldehydes followed by heterogeneous metal reduction. Synthetic strategy involved nucleophillic substitution of hydroxyl protected six membered aliphatic chain on 4,6-dichloropyrimidine followed by Suzuki coupling. This approach is regioselective, efficient and versatile for synthesis of such analogs.

1116-1120

Authors: Nguyen Van Hoang* and Nguyen Cao Tuan*

The degradation studies of picric acid (2,4,6-trinitrophenol, TNP) in water sample through a dielectric barrier discharge (DBD) of atmospheric air cold plasma was carried out. The used DBD reactor consisted of comprised two electrodes that were separated by using an insulating dielectric barrier having a electric discharge voltage varying from of 7.0 to 22.0 kV. The effects of the initial concentration of TNP on the initial degradation rate was investigated methodically. The initial degradation rate was determined experimentally by changing the initial concentrations of TNP between 91.02 and 210.17 mg/L using the DBD of cold air plasma. From experimental results, a kinetic equation for TNP degradation was established based on varying initial concentration as –R = 0.0252CTNP/(1+0.0076CTNP). When 0.0076CTNP << 1, the kinetics of TNP degradation complied with the pseudo-first-order reaction. For TNP degradation kinetics, such as ln (Ct/C0) = 0.0269t + 0.1605, ln (Ct/C0) = 0.0197t + 0.0792, and ln (Ct/C0) = 0.014t + 0.0623, the initial concentrations of TNP were 91.02, 153.3 and 210.17 mg/L, respectively. Moreover, the effect of initial concentration of TNP and the electric power on the degradation efficiency of TNP were determined.

1128-1138

Authors: Meenu Agarwal*, Meenakshi Singh and Jakir Hussain

Water Quality Index (WQI) is a mathematical value for quality of water, which includes the concentration of a number of constituents present in it. Chemical and biological measures of water quality are used to represent water quality index. Measured value of the selected parameters, ideal concentration of that parameter in pure water and standard value given by different quality control organizations are used to determine this number. In the present study, three indexing methods; Weighted Arithmetic Water Quality Index (WAWQI), Groundwater Quality Index (GWQI) and Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) were used to calculate water quality index of groundwater. A hydrochemical analysis of 22 groundwater samples was conducted to evaluate the quality of groundwater for drinking purpose. Ten hydrochemical parameters were selected for computing WQIs of groundwater samples and BIS standards were used for standardization. Analytical results show that 100 % of samples have magnesium and total hardness above the acceptable limit of BIS (10500, 2012). The mean concentration of nitrate was found 196.96 ± 9.3.18 mg/L. Spatial distribution of various parameters shows that south-east part of study area has contaminated groundwater. The results of water quality index shows that drinking water quality of 82 % (WAWQI), 95 % (GWQI) and 77 % (CCME WQI) of groundwater samples were poor to unsuitable type. Water quality index map also reveals that groundwater of village Badhpura, Dhoom Manikpur, Dairy Maccha, Khera Dharampura, Bisrakh road, Duryai and Dujana of district Gautam Budh Nagar of India, was not fit for human consumption.

1145-1150

Authors: J.H. Song*, S.M. Bae, S.K. Cho, J.H. Cho and D.I. Jung*

Robinson′s synthesis has long been a classic in organic chemistry due to its simplicity and impact in the industry. Various modifications have been made to improve the system. Among them, replacing acetone with more acidic chemical equivalents such as calcium dicarboxylic acid or ethyl dicarboxylic acetone improved the yield. In line with this trend, our group previously reported the synthesis of mono- and di-N-substituted tropinone derivatives from the one-pot reaction of 2,5-dimethoxy tetrahydrofuran and various amines with acetonedicarboxylic acid in the presence of HCl and water at room temperature. In this study, the synthesis with acetone instead of acetone-dicarboxylic acid was examined. Mono- and di-N-substituted nortropinones were prepared in higher yields in all cases although there were extent to which yields increased depending on the nature of substituents.

1158-1164

Authors: L. Vaikunta Rao*, K. Tirumala Rao and V.V. Krishna Mohan Kandepi

A simple, linear gradient liquid chromatographic method (RP-HPLC) is proposed for the simultaneous estimation of related compounds in hydroxy naproxen samples. Chromatographic separation was achieved on Zorbax SB C8 (150 × 4.6) mm, 3.5 μm particle size RRLC short column and eluent A used as 0.1% v/v trifluoroacetic acid in water and eluent B used as acetonitrile using Agilent RRLC (UHPLC) system. The mobile phase flow rate was 1.0 mL/min and the eluted compounds were monitored at 235 nm for related substance method and assay method. The excellent resolution was obtained between hydroxy naproxen and its related compounds, which were eluted within 25 min. The performance of the method was validated with respect to ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision and robustness. The correlation coefficient(r) was > 0.995 for both the methods from linearity data and percentage of recovery is 98.0 to 102.0 for assay method and 80.0 to 120.0% for related substance method. Sensitivity of the method was found be less than 0.5 μg/mL. Peak homogeneity data for naproxen in the chromatograms from the selectivity solution obtained by use of the photodiode array detector demonstrated the specificity of the method for analysis of hydroxy naproxen in presence of the related compounds.

1169-1176

Authors: Beena Sheth* and Kaushik Nath

Cascaded electrodialysis system has been developed for increasing the concentration of sulfuric acid from aqueous solution using an interpolymer anion exchange (IPA) membrane. Enrichment process was carried out in a cascade of six electrodialyzers at 20.2 mA/cm2 current density. The performance of the process was evaluated rigorously in terms of current efficiency, voltage requirements and processability to enrich the acid concentration. The bench-scale experimental results exhibited the ability of membrane to perform as a low proton leakage membrane and to enrich the sulfuric acid concentration up to 27.93 wt. %. The higher values of current efficiencies were reported to be in the range of 50 to 60 %. Proton leakage through the membrane, acid back diffusion, concentration polarization and solution conductivity were considered to be the limiting factors for acid enrichment and their effects were found significant on current efficiency and voltage requirement.

1183-1190

Authors: K. Durga Raja*, V. Saradhi Venkata Ramana, K. Raghu Babu, B. Kishore Babu, V. Jagadeesh Kumar, K.S.R. Pavan Kumar and Hemant Kumar Sharma

Development and validation of six potential impurities by ultra performance liquid chromatography electro spray ionization tandem mass (UPLC-ESI-MS/MS) method for dronedarone hydrochloride drug was accomplished coherent with ICH guidelines. Successful chromatographic separation of dronedarone with its six impurities was attained by using gradient elution mode on RP-UPLC column using three pump mode system of 0.1 % formic acid in water as mobile phase A, methanol as the mobile phase B and solvent mixture of methanol, acetonitrile and water in the ratio of 65:30:5 v/v/v as the mobile phase C. Chromatographic conditions were set as 0.3 mL min-1 flow rate at the column temperature of 45 °C with the injection volume 2 μL. Briefly, the method enabled quantitation of six impurities with high accuracy (recovery > 90 %) and precision (% RSD < 5.0),within the ranges of 0.18-2.82 μg g-1. The regression (r) for each impurity over a range was > 0.99. The detection limit and quantitation limit of impurities were set at 0.09 and 0.18 μg g-1, respectively. The performed validation tests proved the suitability of the method for its intended purposes.

1197-1202

Authors: Consolacion Y. Ragasa*, Glenn G. Oyong, Maria Carmen S. Tan, Mariquit M. De Los Reyes and Maria Ellenita G. De Castro

Ergosterol peroxide (1) and ergosterol (2) were commonly isolated as the major compounds of Philippine mushrooms. Sterols 1 and 2 from the dichloromethane extract of Geastrum triplex and Termitomyces clypeatus, respectively, were evaluated for their cytotoxic activities against four human cancer cell lines, viz., breast cancer (MCF-7), colon cancer (HT-29), leukemia (THP-1), and small lung cell carcinoma (H69PR), and a human normal cell line, human dermal fibroblast-neonatal (HDFn), using the PrestoBlue® cell viability assay. Compounds 1 and 2 exhibited the strongest activities against HT-29 with IC50 values of 1.79 and 2.98 μg/mL, respectively, while Zeocin gave an IC50 of 4.89 μg/mL. These compounds also exhibited strong antiproliferative effects against MCF-7 with IC50 values of 4.13 for 1 and 4.20 μg/mL for compound 2, comparable to Zeocin with IC50 = 3.68 μg/mL. Only moderate cytotoxicity resulted when compounds 1 and 2 were tested against H69PR with IC50 values of 7.78 and 6.83 μg/mL, respectively, while Zeocin exhibited an IC50 of 9.81 μg/mL. Furthermore, compounds 1 and 2 showed no effects against THP-1 (IC50 > 100 μg/mL), while Zeocin showed an IC50 of 4.73 μg/mL. Although compounds 1 and 2 have been reported to exhibit different bioactivities in previous studies, the cancer cell lines tested and/or the polarities of the solvents for extraction varied. Therefore, comparisons of the cytotoxic activities of compounds 1 and 2 with earlier studies could not be made extensively.

1207-1211

Authors: Victor Y.A. Barku*, Yaw Opoku-Boahen and Vida Ackon

Seeds of sweet oranges (Citrus sinensis) were analyzed for oil and fatty acid composition. The crude oil was extracted by the use of soxhlet extraction. The results showed that oil content is as high as 71 %. The physico-chemical assessment gave the following results: refractive index (1.457), peroxide value (4.12 meq/kg) and iodine value (34.06 Wijs). The ATR-IR spectrum of oil showed prominent bands at 3008.6, 2921.73, 2852.7, 1742.86, 1709.23, 1460, 1167.66, 1117.39 and 1051.16 cm-1 that identified fatty acid composition. The percentage compositions of various classes of fatty acids present in the oil were polyunsaturated fatty acids (PUFAs, 39.82 %), monounsaturated fatty acids (MUFAs, 57.08 %) and saturated fatty acids (SFAs, 3.09 %). The oil has linoleic acid (18:2, n-6) as the only PUFA and the second highest fatty acid composition (25.63 %). Palmitoleic acid is the highest MUFA (56.30 %) as well as the highest fatty acid composition while capric acid (C10:0) is the lowest fatty acid (0.02 %). These results and in addition to the low compositions of erucic acid, behenic acid and lignoceric acid indicated that the seed oil of sweet orange is possible suitable for both human consumption and industrial purposes.

1221-1229

Authors: Satish Kumar*, P.K. Santra, J. Dwivedi and R.C. Aryan

The present study reports the synthesis and characterization of novel molecules inhibiting the spread of hepatitis C. The molecules were designed as to block the NS3/4A protease enzyme on HCV RNA. The molecules were synthesized using usual peptide synthesis techniques. Compounds with purity more than 95% were characterized and docking studies were also performed. All the compounds were characterized using physico-chemical techniques such as determination of melting point by DSC and NMR, mass, IR spectral studies. The docking studies were also conducted to assess the activity of molecules for inhibition of hepatitis C virus.

1235-1242

Authors: Ayusman Swain and Hariprasad P.*

Cyperus articulatus is widely distributed in Indian subcontinent and its rhizome has been used as folk medicine in different geographical regions for treatment of diseases like malaria, epilepsy and dysentery. In present study the rhizome extracts were studied to identify the natural inhibitor compounds for α-amylase and α-glucosidase. Among six different solvent extracts of the rhizome, the acetone extract which showed to have highest phenolics and flavonoids exhibited α-glucosidase inhibition (IC50 9.1 μg/mL). Different fractions were collected using column chromatography and flash chromatography to analyze the active fractions. Two major fractions significantly showed high enzyme inhibitory activity. In HRLC-MS/MS phenolic as well as non-phenolic class of compounds were identified such as quercetrin, dihydroquercetin, mycophenolic acid, koparin-2-methylether, C16-sphinganine, embelin, phytosphingosine, colforsin, 7,8-dihydroxystearic acid and palmitic acid derivative. The two active fractions having IC50 8.38 and 7.65 μg/mL, were shown to exhibit competitive and mixed type inhibition, respectively. Molecular docking analysis of the compounds with the α-glucosidase active site showed that the phenolic class of compounds have efficient binding with one of the aspartate (Asp66, Asp349 and Asp212) residues whereas there was non-polar contacts with other residues in case of non-phenolic compounds such as long chain hydroxyl acids. The results suggest that Cyperus articulatus rhizome is a potential source of drug ingredients for the management of type-II diabetes.

1248-1250

Authors: Tan Phat Dao, Hoang Thang Do, Le Quang Khoi, Nguyen Van Gia Phap, Mai Huyng Cang, Tri Nhut Pham* and Nguyen Van Muoi*

The lemongrass (Cymbopogon citratus L.) essential oil plays a vital role as an ingredient in different fields due to aromatic, antibacterial properties and antifungal activity. In this study, essential oil of lemongrass was obtained using hydrodistillation method and evaluated for chemical compositions and physico-chemical characteristics. The averaged physico-chemical parameters were determined as specific gravity (0.8865 g/cm3), acid index (2.948), ester index (6.402) and refractive index (9.35). Moreover, the hydrodistillation process performance was achieved 0.29%. The composition of essential oils was analyzed by GC-MS, revealing a total of 18 volatile constituents existing in the lemongrass oil. The major components were α-citral (40.838%), β-citral (28.494%), β-myrcene (16.654%), 2,3-dehydro-1,8-cineole (2.264%) and geraniol (2.388%). The citral component accounts for high content (more than 70% of volume) of oil.

1255-1258

Authors: Nakul Kumar, Chhagan Lal*, Bijendra Singh and Angik K. Patel

The synthesis of spiropyrrolidines by the Knoevenagel condensation has been reported as highly bioactive natural and synthetic organic products. The synthesis was initiated by Knoevenagel condensation of indole-2-one with an appropriate benzaldehyde in presence of L-proline to afford spiropyrrolidines. Herein, a design and pathway of syntheses of a library of spiropyrrolidines bearing spiro heterocyclic indeno[1,2-b]quinoxaline-11-one motifs were reported, which also demonstrated an exceptional inhibitory activity against the anticancer cells. A novel series of dispiroindenoquinoxaline pyrrolizidines were synthesized by the condensation of indeno[1,2-b]quinoxalin-11-one and starting material (a product of ninhydrin and aldehyde derivatives). The structure of the synthesized compounds was established by spectral data.