(E)-3-(2-Methyl-1H-indol-3-yl)-1-(4-methylphenyl)propenone has been prepared, and its crystal structure (C19H17NO, Mr = 275.34) has been determined by single-crystal X-ray diffraction analysis. The title compound crystallized in the triclinic system with space group P1 and unit cell parameters: a = 9.4014 (5) ?, b = 9.8347 (4) ?, c = 10.0318 (5) ?, ? = 62.821 (3)°, B = 85.539 (3)°, ? = 65.262 (3)° and Z = 2. The final reliability index is 0.053 for the 2807 observed reflections. The title compound is linked through N–H···O hydrogen bonds.
The immobilized NaHSO4·H2O on activated charcoal was used as a highly efficient promoter system for facile N-formylation of amines with ethyl formate. All reactions were carried out in refluxing ethyl formate (54 ?C) under mild conditions within 10-100 min to afford the product formamides in high to excellent yields (80-94%).
The E-1,3-diaminoethenyl functional group is a potentially useful synthon. A number of examples of E-1,3-diaminoethenyl functional groups were prepared in good yield starting from an E-enol tosylate of a serine based diketopiperazine and 1°- or 2° amine nucleophiles. The reaction proceeds via a stereoselective nucleophilic substitution pathway.
A series of new Schiff bases of 4-(methylthio)benzaldehyde derivatives 3(a-i) were synthesized by the reaction of 4-(methylthio)benzaldehyde with various amines 2(a-i). Newly synthesized compounds were characterized by elemental analyses, UV-visible, FT-IR, Mass and 1H NMR spectral studies. All compounds were evaluated for their in vitro antibacterial activity against clinically isolated strains i.e., E. Coli, P. Fluorescence, M. Luteus and B. Subtilis. These compounds were screened for their antioxidant activity by 2,2-diphenyl-1-picryl-hydrazyl (DPPH•) and ferrous ion chelating assay (Fe2+) methods. The cytotoxicity assay was performed by tryphan blue dye exclusion method. Compounds 3g, 3h and 3i exhibited good antibacterial activity when compared with other compounds in the series against tested pathogenic bacterial strains. All the compounds showed antioxidant activity, where compound 3b was the best radical scavenger and Fe2+ ion scavenger. These findings showed that the Schiff bases of 4-(methylthio)benzaldehyde derivatives possess antioxidant activity with different mechanism of actions towards the different free radicals tested. Among these derivatives, 3b and 3h had the strongest activity against human peripheral lymphocytes.
In our present investigation a new series of nucleoside derivatives (2-13) were synthesized from uridine (1) via only two step reactions by direct acylation method. Firstly, uridine (1) was treated with 4-t-butylbenzoyl chloride in pyridine at -5?C and afforded the 5´-O-(4-t-butylbenzoyl)uridine derivative (2) in an excellent yield. In order to obtain newer products, the 5´-O-uridine derivative was further transformed to a series of 2´,3´-di-O-acyl derivatives (2-13) containing a wide variety of functionalities in a single molecular framework. The yields of the compounds were more than 80%. The synthesized titled compounds were characterized by their physical properties, FTIR (Fourier transform infrared spectroscopy), 1H-NMR (Nuclear magnetic resonance) spectroscopy and elemental analysis.
Two potential energy surfaces 1 2A1 and 1 2B1 for linear geometry of F-H-Br system have been computed with aug-cc-pVQZ basis set using dynamically weighted state averaged MCSCF followed by MRCI-F12 method. State 1 2A1 has smaller barrier height (3.49 kcal/mol) than 1 2B1. (13.6 kcal/mol). The latter has deep van der Waals well in Br-HF valley (2.12 kcal/mol).
With the focus on calculating the equilibrium constant (Ka) of arsonic acids (RAsO(OH)2) in aqueous media, the behavior of both neutral and negatively charged species of some arsonic acids have been considered through the isodesmic reaction scheme with polarized continuum model of solvation. The relative pKa values of a number of arsonic acids were calculated using density functional theory (DFT), with methylarsonic acid (CH3AsO(OH)2) used as a reference molecule. Various basis sets such as (6-31G(d), 6-31+G(d), 6-311++G(d,p) and 6-311++G(2d,2p)) in conjunction with B3LYP computational method were examined. Finally the latter one was found to give better results. The results of applied B3LYP 6-311++G(2d,2p) method for pKa values of 25 arsonic acids in aqueous media showed good agreement with corresponding experimental pKa values. In this level of theory the average error was less than 0.3 pKa units. The type of substituent affected the acid strength, with electron withdrawing substituents lowering the pKa and electron releasing groups increasing it.
Facile conversion of structurally different epoxides to the corresponding B-chlorohydrins was carried out successfully with anhydrous ZnCl2 in CH3CN. The reactions were carried out within 10-50 min to give B-chlorohydrins with perfect regioselectivity and high yields (80-97%).
This paper describes a harmless HPLC technique for detecting imidacloprid (ICP) and its metabolite, 6-chloronicotinic acid (6CA), using an isocratic 100 % water mobile phase. Chromatographic separations were performed a Daisopak® SP-200-3-C1-P with water mobile phase and a photodiode-array detector. The total run time was & LT; 6 min. The system suitability was well within the international acceptance criteria. The detection limits were 0.018 ?g/ml for ICP and 0.005 ?g/ml for 6CA, respectively. A harmless HPLC method for simultaneous detecting ICP and 6CA was developed and may be further applied to the quantification in animal-derived foods.
Piroxicam (POC) and oxfendazole (OFA) are two widely used veterinary non-steroidal anti-inflammatory and anthelmintic medicines, respectively. Simple, precise and accurate and cost-effective methods for the determination of POC and OFZ in bulk drug and in its dosage forms have been developed and validated. The methods are based on the potentiometric titration of compound with acetous perchloric acid in glacial acetic acid medium using modified glass-saturated calomel electrode system. The methods are applicable over the ranges 1.5 - 15 mg and 7.5-15 mg, for POC and OFA, respectively. The proposed methods were successfully applied to the determination of active substances in their pharmaceutical dosage forms. A statistical comparison was made on the results of proposed methods with those obtained for reference method. The intra-day and inter-day precision and accuracy values obtained were satisfactory with RSD and RE values less than 3%. Excipients in tablets did not interfere to the assay as shown by the recovery study via standard addition technique with mean percentage recoveries in the range 97.8 – 100.6%.