The structures of 4-methoxy-2,6-dimethylbenzonitrile N-oxide (I), 4-bromo-2,6-dimethylbenzonitrile N-oxide (II) and 2,4,6-trimethylbenzonitrile N-oxide (III)

Intramolecular geometry and intermolecular interactions of the CNO group of crystalline benzonitrile oxides: a comparison with phenyl cyanates, phenyl isocyanates, and phenyl azides

Crystal structures of four halogenated benzonitrile oxides allow intramolecular geometry and packing motif comparison with phenyl cyanates, isocyanates, and azides.

Synthesis and anticancer activity of novel spiro-isoxazoline and spiro-isoxazolidine derivatives of α-santonin

In the present study, novel spiro derivatives of α-santonin were prepared and tested for their anticancer activity against a panel of six human cancer cell lines. Spiro-isoxazoline and spiro-isoxazolidine derivatives have been generated on C-ring of α-santonin (α-methylene-γ-butyrolactone) by the 1,3-dipolar cycloaddition of α-santonin derivative 6 with nitrile oxides 7 and nitrones 9 respectively. Among all, compound 10b″ had shown IC50 of 0.01, 0.5 and 0.3 μM against PC-3, THP-1 and MCF-7 cell lines respectively. Further, flow cytometry studies showed that PC-3 cells treated with the spiro-isoxazolidine derivative 10b″ were arrested in the sub G1 phase of the cell cycle in a concentration dependent manner. The spiro-isoxazolidine derivative 10b″ also showed concentration dependent inhibitory activity against NF-κB, p65 with 57% inhibition in 24 h at 10 μM.

Design and synthesis of spiro derivatives of parthenin as novel anti-cancer agents

Several novel spiro derivatives of parthenin (1) have been synthesized by the dipolar cycloaddition using various dipoles viz; benzonitrile oxides, nitrones and azides with exocyclic double bond of C ring (α-methylene-γ-butyrolactone). Majority of the compounds exhibited improved anti-cancer activity compared to the parthenin, when screened for their in vitro cytotoxicity against three human cancer cell lines viz., SW-620, DU-145 and PC-3. In vivo screening of select analog revealed improved anti-cancer activity with low mammalian toxicity as compared to parthenin. The results of the cytotoxicity pattern of these derivatives reveals the SAR of these sesquiterpinoid lactones and possible role of α,β-unsaturated ketone of parthenin in inhibiting NF-kB. A mechanistic correlation of anti-cancer activity along with in vivo and western blotting experiments has been described.