Sasikala Ramalingam, Thirumurthy Kannan, Mayavel Perumal, Thirunarayanan Ganesamoorthy
Department of Chemistry, Annamalai University, Annamalai, Nagar 608 002, India.
Org Med Chem Lett. 2012 Jun 11;2(1):20. doi: 10.1186/2191-2858-2-20.
Green catalyst fly ash: H2SO4 was prepared by mixing fly ash and sulphuric acid. Microwave irradiations are applied for solid phase cyclization of 5-bromo-2-thienyl chalcones and phenyl hydrazine hydrate in the presence of fly ash: H2SO4 yields, 1-phenyl-3(5-bromothiophen-2-yl)-5-(substituted phenyl)-2-pyrazolines. These pyrazolines were characterized by their physical constants and spectral data. The antimicrobial activities of all synthesized pyrazolines have been studied.
Scanning electron microscopy (SEM) analysis shows the morphology changes between fly ash and the catalyst fly ash: H2SO4. The SEM photographs with the scale of 1 and 50 μm show the fly-ash particle is corroded by H2SO4 (indicated by arrow mark), and this may be due to dissolution of fly ash by H2SO4. The yields of 1-phenyl-3(5-bromothiophen-2-yl)-5-(substituted phenyl)-2-pyrazolines is more than 75% using this catalyst under microwave heating. All pyrazolines showed moderate activities against antimicrobial strains.
We have developed an efficient catalytic method for synthesis of 1-phenyl-3(5-bromothiophen-2-yl)-5-(substituted phenyl)-2-pyrazolines by solid phase cyclization using a solvent-free environmentally greener catalyst fly ash: H2SO4 under microwave irradiation between aryl chalcones and hydrazine hydrate. This reaction protocol offers a simple, economical, environment friendly, non-hazardous, easier work-up procedure, and good yields. All synthesized pyrazoline derivatives showed moderate antimicrobial activities against bacterial and fungal strains.
绿色催化剂粉煤灰：硫酸是通过将粉煤灰与硫酸混合制备而成。在粉煤灰：硫酸存在的情况下，利用微波辐射对5-溴-2-噻吩基查尔酮和水合苯肼进行固相聚环反应，得到1-苯基-3(5-溴噻吩-2-基)-5-(取代苯基)-2-吡唑啉。这些吡唑啉通过其物理常数和光谱数据进行表征。对所有合成的吡唑啉的抗菌活性进行了研究。
扫描电子显微镜（SEM）分析显示了粉煤灰与催化剂粉煤灰：硫酸之间的形态变化。放大倍数为1和50μm的SEM照片显示粉煤灰颗粒被硫酸腐蚀（用箭头标记），这可能是由于硫酸使粉煤灰溶解所致。在微波加热条件下，使用该催化剂时，1-苯基-3(5-溴噻吩-2-基)-5-(取代苯基)-2-吡唑啉的产率超过75%。所有吡唑啉对抗菌菌株均表现出中等活性。
我们开发了一种高效的催化方法，即在微波辐射下，使用无溶剂且环境更绿色的催化剂粉煤灰：硫酸，通过固相聚环反应由芳基查尔酮和水合肼合成1-苯基-3(5-溴噻吩-2-基)-5-(取代苯基)-2-吡唑啉。该反应方案提供了一种简单、经济、环境友好、无危险、后处理程序简便且产率高的方法。所有合成的吡唑啉衍生物对细菌和真菌菌株均表现出中等抗菌活性。
