Synthesis and cytotoxic activity of γ-aryl substituted α-alkylidene-γ-lactones and α-alkylidene-γ-lactams

A series of 5-aryl-3-alkylidenedihydrofuran-2(3 H)-ones and 5-aryl-3-methylidenepyrrolidi-2-nones were synthesized starting from 4-aryl-2-diethoxyphosphoryl-4-oxobutanoates. Target compounds were evaluated for their cytotoxic activity against L-1210, HL-60 and NALM-6 cell lines. A series of 5-aryl-3-alkylidenedihydrofuran-2(3 H)-ones 6a– g″ and 11a, b as well as 5-aryl-3-methylidenepyrrolidin-2-ones 10a– c and 12 were synthesized starting from 4-aryl-2-diethoxyphosphoryl-4-oxobutanoates 3a– g. Reaction sequence includes reduction or reductive amination of the carbonyl group, lactonization or lactamization step and finally the Horner–Wadsworth–Emmons olefination of aldehydes using thus obtained 5-aryl-3-diethoxyphosphoryl-3,4-dihydrofuran-2(5 H)-ones 5a– g″ or 5-aryl-3-diethoxyphosphorylpyrrolidin-2-ones 9a– c. Furanones 6 and 11, as well as pyrrolidinones 10 and 12, were evaluated in vitro against mouse leukemia cell line L-1210 and two human leukemia cell lines HL-60 and NALM-6. Several of the obtained furanones proved to be very potent against all three cell lines with IC 50 values lower than 6 μM. Structure–activity relationships of these compounds, as well as 5-alkyl or 5-arylmethyl-3-methylidenedihydrofuran-2(3 H)-ones 13a– e, previously obtained in our laboratory, are discussed.