Background: Thiophene, thiazole, and isoxazole derivatives are present in a wide range of natural and synthetic compounds with heterogeneous pharmacological activity. Due to their structural diversity, they are some of the most versatile classes of compounds for anticancer drug design and discovery. Objective: Thiophene, thiazole, and isoxazole derivatives were herein designed with a dual purpose: as antiproliferative agents and kinase inhibitors. Methods: The test compounds were synthesized in moderate to high yields through a simple methodology. Tetrahydrobenzo[b]thiophen-5-one derivatives 5a-f were prepared from the reaction of 2-arylidencyclohexan- 1,3-dione 3a-c with elemental sulfur and either of malononitrile (4a) or ethyl cyanoacetate (4b) in 1,4-dioxan in the presence of triethylamine. Compounds 5a,b were used for the synthesis of thiophene, thiazole, and isoxazole derivatives through their reactions with different chemical reagents. Results: Antiproliferative evaluations, c-Met kinase, and Pim-1 kinase inhibitions were performed where some compounds revealed high activities. In all cases, antiproliferative activity and the kinase inhibitions were performed against six cancer cell lines and five tyrosine kinases, respectively. Where the most cytotoxic compounds were 3c, 5d, and 16c with IC50’s 0.29, 0.68, and 0.42μM, respectively, against the A549 cell line. Conclusion: The anti-proliferative activities of the newly synthesized compounds were evaluated against the six cancer cell lines (A549, HT-29, MKN-45, U87MG, SMMC-7721, and H460). The most potent compounds toward the cancer cell lines (3a, 3c, 5d, 7c, 11c, 16a, and 16c) were further investigated towards the five tyrosine kinases (c-kit, FIT-3, VEGFR-2, EGFR, and PDGFR). Compounds 3c, 5d, and 16c were selected for testing of their inhibition for the Pim-1 kinase due to their anti-proliferation activities against the cancer cell lines and their high activities against the tyrosine kinases.

Cyclohexan‐1,3‐dione (1) was used as the key starting material, which reacted with salicylaldehyde (2) and either malononitrile (3a) or ethyl cyanoacetate (3b) in ethanol containing a catalytic amount of triethylamine to give the 3,4,7,12b‐tetrahydrochromeno[3,4‐c]chromen‐1‐one derivatives 5a,b. The latter compounds underwent Gewald's thiophene synthesis through the reaction with either malononitrile or ethyl cyanoacetate to give compounds 6a‐d, respectively. On the other hand, compound 5a was used for the synthesis of annulated chromeno[3,4‐c]chromen derivatives through its reaction with different chemical reagents. The synthesized compounds were evaluated against the six cancer cell lines A549, HT‐29, MKN‐45, U87MG, SMMC‐7721, and H460 using the standard MTT assay in vitro, with foretinib as the positive control, many compounds expressed high inhibitions. The most active compounds 5b, 6b, 6d, 7, 9b, 11a, 11b, 13, 17, 18b, 20b, 21b, 21e, and 21f were selected for inhibition of five tyrosine kinases and some selected compounds for Pim‐1 kinase inhibition. The results showed that compounds 6b, 6d, 11a, 13, 17, 20b, and 21e were the most potent compounds with the tyrosine kinases and compounds 6d, 11a, 20b, and 21e were the most potent inhibitors of Pim‐1 kinase.