Solvent-free synthesis of pyrano[2,3-d]pyrimidine-2,4(1H,3H)-diones by ball-milling and without any catalyst is described. This method provides several advantages such as being environmentally friendly, using a simple workup procedure, and affording high yields.

With the aim of discovering potential cytotoxic agents, a series of benzochromene derivatives were screened for their cytotoxic activity against seven human cancer cell lines by standard 3-(4, 5-dimethyl thiazol)-2,5-diphenyl tetrazolium bromide (MTT) assay. Apoptosis, as the mechanism of cell death, was investigated morphologically by acridine orange/ethidium bromide staining and cell surface expression assay of phosphatidylserine by Annexin V-PE/7-AAD technique. The effects of compounds on reactive oxygen species (ROS) and nitric oxide (NO) generations in three human breast cancer cell lines were also studied. All compounds showed significant cytotoxic activity with inhibitory concentration (IC50) values in the micromolar range (4.6-21.5 μM). The results of apoptosis evaluation suggested that the cytotoxic activity of these compounds in breast cancer cells occurs via apoptosis. MCF-7 cell line showed higher levels of ROS and NO production after treatment with compounds. The increase in ROS production after 4 and 24 h indicated that one of the ways that these compounds can induce apoptosis is by increasing ROS generation. Cytotoxic and apoptotic effects of these compounds in human cancer cells indicated that they can be a good candidate for further pharmacological studies to discover effective anticancer agents.

Solvent-free one-pot synthesis of 2-amino-4H-chromene scaffold is described in a very simple, efficient, and environmentally benign method using sodium carbonate as a cheap and non-toxic catalyst with up to excellent yields.

Various 2-amino-4-aryl-3-cyano-4H-chromenes have been quantitatively prepared by dry ball milling in the presence of catalytic Na2CO3. The orientation specificities are discussed; existing misattributions are pointed out and clarified by NMR.

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