Sodium Bisulfite as an Efficient and Inexpensive Catalyst for the One-pot Synthesis of 2,4,5-Triaryl-1H-imidazoles from Benzil or Benzoin and Aromatic Aldehydes
AbstractA new, convenient, and efficient method for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones is developed starting from phthalhydrazide, aromatic aldehydes, and malononitrile using 4-N,N-dimethylaminopyridin as catalyst. This modified route provides much higher yields and a simple work-up procedure of products. Also this methodology is of interest due to the use of ethanol as a solvent without use of any toxic metals as catalyst, thus minimizing the cost, the operational hazards, and environmental pollution.
Melamine trisulfonic acid was used as an efficient and recyclable catalyst for the one-pot synthesis of 10-aryl-6,8-dimethyl-6,10-dihydro-5-oxa-6,8-diazaanthra[2,3-d][1,3]dioxole-7,9-diones by condensation of 3,4-methylene dioxyphenol, aromatic aldehydes and 1,3-dimethylbarbituric acid under solvent-free conditions. Different types of aromatic. aldehydes were used in the reaction and in all cases the products were obtained in good to excellent yields.
Abstract
ZnO nano-powders were used for the one-pot synthesis of pyrano[2,3- d]pyrimidines via the solvent-free multi-component reaction of aromatic aldehydes, 1,3-dimethylbarbituric acid and malononitrile, in good to excellent yields of products.
Melamine Trisulfonic Acid: An Efficient, Heterogeneous and Reusable Catalyst for the Synthesis of 10-Aryl-6,8-dimethyl- 6, 10-dihydro-5-oxa-6,8-diazaanthra [2,3-d][1,3]dioxole- 7,9-diones