A simple, novel, efficient and three-component procedure for the synthesis of pyrimido[4,5-d]pyrimidine-2,4-dione derivatives by the reaction of 6-amino-1,3-dimethyluracil, aldehyde and 2-benzylisothiourea hydrochloride promoted by ionic liquid 1-butyl-3-methylimidazolium bromide ([BMIm]Br) under solvent-free conditions is reported. The presented method is benefited from operational simplicity, simple workup and reusability of ionic liquid. These products were evaluated in vitro for their antibacterial activities. Manuscript profile

An efficient and green method for the synthesis of pyrano[3,2-c]chromene or pyrano[4,3-b]pyrone derivatives is described by using a three-component condensation process of malononitrile, aldehyde, and 4-hydroxycoumarine or 4-hydroxypyrone in [BMIm]BF4-LiCl as an ionic liquid. Manuscript profile

A practical and green method for the synthesis of 5H-dibenzo[b,i]xanthene-tetraones and spiro[dibenzo[b,i]xanthene-13,3'-indoline]-pentaones by the condensation of 2-hydroxynaphthalene-1,4-dione with aldehydes or isatins, respectively, in the presence of a catalytic amount of cellulose sulfuric acid (CSA) under solvent-free conditions at 100 °C is described. The significant features of this procedure are high yields of the products, simple work-up, solvent-free conditions, operational simplicity and non-toxicity of the catalyst. Moreover, cellulose sulfuric acid is successfully reused for four cycles without significant loss of activity. Manuscript profile