Design, synthesis and cytotoxicity of novel chalcone analogs derived from 1-cyclohexylpyrrolidin-2-one and 2,3-dihydrobenzo[f]chromen-1-one

Two divergent series of novel chalcone analogs, one derived from 1-cyclohexylpyrrolidin-2-one and the other derived from 1-benzo[f]chromanone, were designed, synthesized and evaluated for cytotoxicity against two murine cancer cell lines. Two 1-benzo[f]chromanone analogs, 4g and 4j yielded moderate toxicity against both melanoma B16 and lymphoma L1210 cell lines with IC ₅₀ values between the range of 5 and 6μM. With an IC ₅₀ value of 3.4μM, compound 4g was also active against human MDA-MB-435 melanoma cells. X-ray structures of the β-hydroxy ketone product (4a) and the α,β-unsaturated ketone (4h) were collected, and confirm the syn-configuration between the carbonyl moiety and the β-vinylic proton in 4h. X-ray structures of two 1-cyclohexylpyrrolidin-2-one derivatives were also obtained, and both showed an E-configuration for the double bond. Twenty-four chalcone analogs and one aldol product derived from 1-benzo[f]chromanone and N-cyclohexylpyrrolidinone were synthesized and tested for cytotoxicity against murine cancer cells B16 and L1210. One 1-benzo[f]chromanone derivative (4g), containing a 3,4,5-trimethoxy benzylidene moiety, was quite active also against human MDA-MB-435 melanoma cells. The structure and conformation of the target compounds were ascertained by single crystal X-ray analysis of four compounds.