Acetylation of Phenols, Anilines, and Thiols Using Silica Sulfuric Acid under Solvent-Free Conditions

Silica sulfuric acid was employed as a heterogeneous catalyst for the acetylation of a variety of phenols, amines, and thiols under solvent-free conditions at room temperature. Deactivated substrates also acetylated rapidly, and the method showed the preferential selectivity for acetylation of amino group in the presence of hydroxyl groupinwhich no C-acylation was observed

Synthesis of 1,4-Dihydropyridines Bearing a Carbamate Moiety on the 4-Position

A good range of 1,4-dihydropyridines bearing a carbamate moiety on the 4-position were synthesized from the primary reaction of different hydroxyaldehydes with phenyl isocyanates and the subsequent reaction of the obtained carbamates with methyl acetoacetate in the presence of ammonium fluoride. When phenyl isothiocyanate was used in place of phenyl isocyanate in the same condition, the reaction did not take place

Evaluation of MARS for the spatial distribution modeling of carbon monoxide in an urban area

Spatial distribution modeling of CO in Tehran can lead to better air pollution management and control, and it is also suitable for exposure assessment and epidemiological studies. In this study MARS (Multi–variate Adaptive Regression Splines) is compared with typical interpolation techniques for spatial distribution modeling of hourly and daily CO concentrations in Tehran, Iran. The measured CO data in 2008 by 16 monitoring stations were used in this study. The Generalized Cross Validation (GCV) and Cross Validation techniques were utilized for the parameter optimization in the MARS and other techniques, respectively. Then the optimized techniques were compared based on the mean absolute of percentage error (MAPE). Although the Cokriging technique presented less MAPE than the Inverse Distance Weighting, Thin Plate Smooth Splines and Kriging techniques, MARS exhibited the least MAPE. In addition, the MARS modeling procedure is easy. Therefore, MARS has merit to be introduced as an appropriate method for spatial distribution modeling. The number of air pollution monitoring stations is very low (16 stations for 22 zones) and the distribution of stations is not suitable for spatial estimation, hence the level of errors was relatively high (more than 60%). Consequently, hourly and daily mapping of CO provides a limited picture of spatial patterns of CO in Tehran, but it is suitable for estimation of relative CO levels in different zones of Tehran. Hence, the map of mean annual CO concentration was generated by averaging daily CO distributions in 2008. It showed that the most polluted regions in Tehran are the central, eastern and southeastern parts, and mean annual CO concentration in these parts (zones 6, 12, 13, 14 and 15) is between 4.2 and 4.6 ppm

Silica Sulfuric Acid as an Efficient Heterogeneous Catalyst for the Solvent-Free Synthesis of 1-Substituted 1H-1,2,3,4-Tetrazoles

Silica sulfuric acid (SSA) was found to be an efficient heterogeneous catalyst for the synthesis of 1-substituted 1H-1,2,3,4-tetrazoles from the reaction of primary amines with triethyl orthoformate and sodium azide under thermal and solvent-free conditions

Change in several Antioxidant Enzymes Activity and Seed Yield by Water Deficit Stress in Soybean (Glycine max L.) Cultivars

Drought stress is one of several environmental factors greatly limiting crop production. In order to study the effect of water deficit on antioxidant enzymes activity and seed yield of five soybean cultivars, an experiment was conducted in two growing seasons in 2008 and 2009. The experimental design was randomized complete block in a split plot arrangement with four replications. Irrigation treatments were (S1, 50; S2, 100 and S3, 150 mm evaporation from the Class “A pan” evaporation) and cultivars were (‘L17’, ‘Clean’, ‘T.M.S.’, ‘Williams*Chippewa’ and ‘M9’). The results showed that, water deficit stress increased antioxidants content [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX)] significantly, but content of them were more at mild than high water deficit stress (S2>S3>S1). Furthermore, water deficit stress, decreased total chlorophyll content, number of pods per plant, thousand seed weight, seed yield and harvest index in all of cultivars. Among cultivars, ‘L17’ and ‘Williams*Chippewa’ produced the highest seed yield at the optimum condition of irrigation and both water deficit stress levels, respectively. Assessment of correlation results indicated that, there was a positive and significant correlation among SOD and seed yield in both water deficit stress levels, too

Chemical and biochemical responses of soybean (Glycine max L.) cultivars to water deficit stress

Abstract Plant responses to oxidative injuries and content of antioxidants were comparatively studied in five soybean cultivars (L 17 , Clean, T.M.S, Williams×Chippewa and M 9 ) at the three levels of irrigation. In order to measure the water deficit stress, the irrigation was applied based on three levels of evaporation from the 'class A' pan (50 mm; optimum condition of irrigation, 100 mm; moderate water deficit and 150 mm; extreme water deficit). A two-year field experiment was conducted in 2008 and 2009. The experimental design was a split plot in a randomized complete block design with four replications. The output results showed that, water deficit stress significantly increased activities of some antioxidant enzymes (catalase and glutathione redoctase) as well as ABA and Proline content. Lipid and protein oxidation (malondialdehyde and dityrosine contents) also increased significantly at the moderate and extreme water deficit stress. The relative water content, seed and oil yield were affected by water deficit and were reduced by both levels of water deficit. Among cultivars, L 17 and Williams×Chippewa produced the highest seed and oil yield at the optimum condition of irrigation and both levels of water deficit stress, respectively. Assessment of correlation results indicated that, there was a positive and significant correlation among activity of antioxidant enzymes, ABA and proline content with seed and oil yield in both levels of water deficit stress, as well

Exploring the Possibility of Discharge of Nitrogen from the Lower Part of the Soil by two Between-crops Plant of Perko and Buko in order to better Use and Prevent the Waste of Nitrogen

Since the nitrogen is one of the essential elements of plant with high mobility and tremendous waste, some cover crops with improved root system probably can prevent leaching of this element. This study was done in Agricultural Research Station of Islamic Azad University of Karaj located in Mahdasht area during the crop year 2013-2014. This study was done by using factorial experiment in a randomized complete block design with two cultivars of Brassica family of Perko and Buko, 3 levels of nitrogen (N0, N150, N300) Kg per ha, from urea source (due to nitrogen use efficiency in Karaj) at two different depth of 0-30 and 30-60 cm of soil. The research results showed that the triple interaction of in-depth plant at nitrogen on root fresh weight, root dry weight, the percentage of nitrogen in depth of 30 cm, 60 cm depth of soil nitrogen, at probability level of 1% and the percentage of organic carbon (P <0.05) among the studied plants is significant. The comparisons showed that Buko at the highest amount of applied nitrogen in the soil (300 kg N ha) left less nitrogen in the soil. The lowest amount of nitrogen leaching was for a depth of 30 cm and at 150 kg of nitrogen per hectare which belonged to Perko. By using high levels of nitrogen in the soil the waste and leaching of this element was tremendous. Therefore, Perko root fresh weight and root dry weight at 150 kg nitrogen per hectare were the highest at 30 cm depth of soil. Control plants had low root dry weight yield and aerial dry weight yield. Buko root length at a 60 cm depth of soil was higher than Perko so that at this depth of soil Buko was capable than Perko in preventing the nitrogen waste. Buko at high levels of nitrogen had higher nitrogen percentage in root and aerial organ. The protein amount of aerial organ increased with enhancement of nitrogen absorption to plant organs. Buko had more protein than Perko. Buko total dry weight was more than Perko

Synthesis Of Some Novel Silver-Cysteamine Complexes

The aim of this research was to synthesize some new silver-cysteamine complexes of potential biological interest. Reactions were carried out between silver nitrate and cysteamine (2-aminoethanethiol hydrochloride) under different conditions of pH and mole ratios of the metal (silver) to the ligand (cysteamine). Some novel silver-cysteamine complexes were made, and after characterization of the complexes by cyclic voltammetry, pH measurements, and microanalysis, it is now obvious that the mole ratio of the metal to the ligand in complexes is about four to three