Efficient synthesis of aurone Mannich bases and evaluation of their antineoplastic activity in PC-3 prostate cancer cells

Abstract: An efficient method for regioselective synthesis of C-7 Mannich bases of 6-hydroxyaurones was accomplished by the N,N-dialkylaminomethylation using aminals prepared from dimethylamine, dipropylamine, bis(2-methoxyethyl)amine, N-methylbutylamine, N-methylbenzylamine, morpholine, piperidine, and 1-methylpiperazine. Further transformation of 7-(N,N-dialkylamino)methyl group in these aurones led to formation of C-7 acetoxymethyl and methoxymethyl derivatives of 6-hydroxyaurones, some of which showed promising inhibition of PC-3 prostate cancer cell proliferation in the high nanomolar to low micromolar range that exceeded that of cisplatin. Graphical abstract: Compound 12c (R³ = Ac, Ar = 3,4-OMePh) displays 75% inhibition of PC-3 prostate cancer cells proliferation at 300 nM concentration.[Figure not available: see fulltext.]