فهرست مقالات Salicylaldehyde

• دسترسی آزاد مقاله
  • صفحه چکیده
  • متن کامل
  
  1 - Solvatochromic and Photochromic behavior of 1',3',3'-trimethyl-8-nitrospiro[chromene-2,2'-indoline]
  Zeinalabedin Sepehr Hossein Nasr-Isfahani Ali Reza Mahdavian
  1',3',3'-trimethyl-8-nitrospiro[chromene-2,2'-indoline] is one of the spiropyran derivatives. In recent years, the spiropyran derivatives have been studied numerously for their photochromic properties.We know these compounds as an isomeric system. The closed-ring spirop چکیده کامل

  1',3',3'-trimethyl-8-nitrospiro[chromene-2,2'-indoline] is one of the spiropyran derivatives. In recent years, the spiropyran derivatives have been studied numerously for their photochromic properties.We know these compounds as an isomeric system. The closed-ring spiropyran (SP) could be converted into the open-ring merocyanine (MC) upon UV irradiation. In this work, 1',3',3'-trimethyl-8-nitrospiro[chromene-2,2'-indoline] is prepared, and subsequently, characterized by the FT-IR, 1H-NMR, and 13C-NMR spectroscopic techniques. In order to confirm its molecular structure, the UV–visible spectroscopic analysis of its solutions is studied in different solvents in the spectral range of 250-750 nm before and after exposure to a UV lamp. The 1',3',3'-trimethyl-8-nitrospiro[chromene-2,2'-indoline]chromophore shows a solvatochromism behavior: the spiropyran solution in acetonitrile is completely colorless, while its solution is pale blue in DMF and dark purple in ethanol and methanol. The visible spectra of the spiropyran solutions show that the solvents methanol and ethanol are capable of stabilizing the MC form better than the solvents DMF and acetonitrile, and that this photochromic compound has a higher absorption intensity in the visible region. پرونده مقاله
• دسترسی آزاد مقاله
  • صفحه چکیده
  • متن کامل
  
  2 - Ultrasonic-assisted Synthesis of New Generation of Coumarins
  Lia Karimian
  A convenient and efficient procedure for synthesis of Bis(4-HydroxyCoumarin) derivatives has been developed by a simple one-pot, one step ultrasonic-assisted reaction to produce Bis(4-HydroxyCoumarins) in room temperature. The present methodology offers several advantag چکیده کامل

  A convenient and efficient procedure for synthesis of Bis(4-HydroxyCoumarin) derivatives has been developed by a simple one-pot, one step ultrasonic-assisted reaction to produce Bis(4-HydroxyCoumarins) in room temperature. The present methodology offers several advantages, such as a simple procedure with an easy work-up, short reaction times, high yields, and the absence of any volatile and hazardous organic solvents. پرونده مقاله
• دسترسی آزاد مقاله
  • صفحه چکیده
  • متن کامل
  
  3 - PbWO4 nanoparticles: A robust and reusable heterogeneous catalyst for the synthesis of benzopyranopyridines under ultrasonic irradiation
  Hossein Shahbazi-Alavi Javad Safaei-Ghomi Ruhollah Talebi
  An efficient four-component synthesis of benzopyranopyridines is described by one-pot condensation of salicylaldehydes, thiols and 2 equiv of malononitrile with nano-PbWO4 as a robust and reusableheterogeneous catalyst under ultrasonic irradiation. Lead tungstate (PbWO4 چکیده کامل

  An efficient four-component synthesis of benzopyranopyridines is described by one-pot condensation of salicylaldehydes, thiols and 2 equiv of malononitrile with nano-PbWO4 as a robust and reusableheterogeneous catalyst under ultrasonic irradiation. Lead tungstate (PbWO4) nanostructures have been synthesized via a sonochemical method based on the reaction between lead (II) nitrate and sodium tungstate dihydrate in an aqueous solution. Some advantages of this protocol include use of simple and readily available starting materials, rapid assembly of medicinally privileged heterocyclic molecules, reusability of the catalyst, low amount of the catalyst and application of the sonochemical methodology as an efficient technique and innocuous means of activation in synthetic chemistry. پرونده مقاله
• دسترسی آزاد مقاله
  • صفحه چکیده
  • متن کامل
  
  4 - Modification of silica with 2,4-dinitrophenylhydrazanomethylphenol for monosaccharide productions
  Kasim Mohammed Hello Hayder Mihsen  Mosa
  2,4-dinitrophenylhydrazanomethylphenol (DNPHMP) was immobilized onto silicate rice husk ash to form a heterogeneous catalyst denoted as RHDNPH. The elemental and EDX analysis of RHDNPH showed the nitrogen is incorporated into silica. The RHDNPH had 154.6 m2g-1 as a spec چکیده کامل

  2,4-dinitrophenylhydrazanomethylphenol (DNPHMP) was immobilized onto silicate rice husk ash to form a heterogeneous catalyst denoted as RHDNPH. The elemental and EDX analysis of RHDNPH showed the nitrogen is incorporated into silica. The RHDNPH had 154.6 m2g-1 as a specific surface area. The FT-IR clearly showed the appearance of –NH and C=N absorption band at the expected range. The TGA curve shows that the RHDNPH was stable at the temperature of less than 200 °C. Hydrolysis experiments of cellulose were conducted in liquid face reaction at 140 °C, and 150 mg of catalyst mass in 11 h. The maximum hydrolysis of cellulose was 84 % with 100 % selectivity of glucose over the catalyst. The catalyst was simple in its preparation, stable during the cellulose hydrolysis in addition to repeatedly without a significant loss of its catalytic activity. پرونده مقاله