Catalyst-free green synthesis of dihydropyrano[2,3-c]pyrazole scaffolds assisted by ethylene glycol (E-G) as a reusable and biodegradable solvent medium
作者:Farzaneh Mohamadpour
DOI:10.1007/s12039-020-01775-4
日期:2020.12
green ethyleneglycol (E-G) can be recycled at least six times with no considerable reduction in activity making it greatly advantageous in addressing the industrial requirements and environmental worries. Graphic AbstractThe catalyst-free and environmentally friendly synthesis of dihydropyrano[2,3-c]pyrazole scaffolds are reported via ethyleneglycol (E-G) as a green, reusable and biodegradable promoting
摘要我们发现无催化剂,绿色和快速一锅四部分串联的二氢吡喃并[2,3-的准备策略Ç ]吡唑-生物显著支架-通过Knoevenagel反应,迈克尔环合基于绿色化学原则。当前实践的重点是在无害反应条件下的应用,无催化剂,操作简便,使用廉价的引发剂,通过分离纯产物易于过滤,从而避免了对柱色谱法的需求,无金属,优异的收率,节省了反应时间。但是,绿色乙二醇(EG)可以循环使用至少六次,而活性不会显着降低,这使其在满足工业要求和环境问题方面具有极大优势。 图形摘要的二氢吡喃的和环境友好的无催化剂的合成[2,3- c ^ ]吡唑支架报告通过乙二醇(EG),为绿色,可重复使用的和可生物降解促进媒体经由乙酰乙酸乙酯,水合肼/的串联的Knoevenagel -迈克尔反应环化缩合苯肼,芳香族/脂肪族醛和丙二腈提供了预期的产品,具有出色的收率和较短的反应时间,这可能解决了工业上的一些成本问题
Rapid One-pot, Four Component Synthesis of Pyranopyrazoles Using Heteropolyacid Under Solvent-free Condition
作者:Hemant V. Chavan、Santosh B. Babar、Rahul U. Hoval、Babasaheb P. Bandgar
DOI:10.5012/bkcs.2011.32.11.3963
日期:2011.11.20
A series of pyranopyrazoles, was efficiently synthesized via one-pot, four component reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes and malononitrile in the presence of catalytic amount silicotungstic acid under solvent free condition. NOE experiments confirmed that the product exist exclusively in the 2H form. The present protocol offers the advantages of clean reaction, short reaction time, high yield, easy purification and economic availability of the catalyst.
Morpholine triflate promoted one-pot, four-component synthesis of dihydropyrano[2,3-c]pyrazoles
作者:Chen-Feng Zhou、Jian-Jun Li、Wei-Ke Su
DOI:10.1016/j.cclet.2016.05.010
日期:2016.11
Abstract A one-pot, four-component reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes, and malononitrile was discussed using Lewis acid catalyst morpholine triflate (MorT) to afford a series of dihydropyrano[2,3- c ]pyrazoles, which were generally catalyzed by organic alkalis. Moderate to excellent yields, no chromatographic purification, and evasion of environmentally hazardous solvents
Sodium ascorbate as an expedient catalyst for green synthesis of polysubstituted 5-aminopyrazole-4-carbonitriles and 6-amino-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles
作者:Hamzeh Kiyani、Maryam Bamdad
DOI:10.1007/s11164-018-3260-0
日期:2018.4
Sodium ascorbate (SA) was used as a safe catalyst for the synthesis of 5-aminopyrazole-4-carbonitriles from the one-pot three-component cyclocondensation (3-CC) of aldehydes, phenylhydrazine, and malononitrile at 50 °C. This 3-CC proceeds in a mixture of ethanol–water as a green reaction medium to give the desired densely functionalized pyrazoles in good to high yields. 6-Amino-1,4-dihydropyrano-[2
l-Proline as an efficicent catalyst for the multi-component synthesis of 6-amino-4-alkyl/aryl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles in water
作者:Hormi Mecadon、Md. Rumum Rohman、Iadeishisha Kharbangar、Badaker M. Laloo、Icydora Kharkongor、Mantu Rajbangshi、Bekington Myrboh
DOI:10.1016/j.tetlet.2011.04.048
日期:2011.6
An efficient four-component synthesis of 6-amino-4-alkyl/aryl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles involving ethyl acetoacetate, hydrazine hydrate, malononitrile, and various aldehydes using L-proline (10 mol %) in water under mild reaction condition in excellent yields is established. A comparative study of L-proline with gamma-alumina, basic alumina, and KF-alumina was also carried out. The generality and functional tolerance of this convergent and environmentally benign method is demonstrated. (C) 2011 Elsevier Ltd. All rights reserved.