Synthesis of N-Acetyl-3,5-Diaryl-2-pyrazolines from Natural Precursor 2,4,5-Trimethoxy Benzaldehyde (Asaronaldehyde): An Anticancer Studies.

Synthesized substituted N-acetyl-3,5-diaryl-2-pyrazolines through their chalcone intermediates and evaluated for anti-cancer activity. Chalcones were synthesized from 2,4,5-trimethoxy benzaldehyde obtained from oxidation of β-asarone ((Z)-2,4,5-trimethoxy-1-propenylbenzene) is a major active principle component found in Acorus calamus oil (70–80%) and reacting with substituted acetophenones by Claisen-Schmidt condensation. Substituted chalcones were further treated with hydroxylamine in presence of sodium acetate and acetic acid cyclizes to give directly the corresponding N-acetyl-3,5-diaryl-2-pyrazolines in 68–85% yields. Structures were confirmed by IR, GC-MS,1H NMR, and 13C NMR.These novel analogues were evaluated for their in vitro anticancer activity against three human tumor cell lines (MCF-7, SW-982, and HeLa) using MTT assay. The results reveled that among the synthesized pyrazolines, which are having electron donor groups in para position of the aryl ring, i.e. 5th position of the N-acetyl pyrazolines showed better inhibitory activity (5b, 5c, 5d, 5e, 5f, 5g, 5k, and 5j) when compared with β-asarone. The compound 3'-nitro, 4'-chloro pyrazolines (5k) showed highest IC50 values 11.67 ± 0.54, 14.17 ± 0.92, and 18.26 ± 0.98 µg/mL (P <0.05) respectively, when compared to natural precursor. [ABSTRACT FROM AUTHOR]