Iron(III) and BF3·OEt2-Promoted O-Transfer Reaction of N-Aryl-α,ß-Unsaturated Nitrones to Prepare Difluoroboron ß-Ketoiminates.

We described an iron(III) and BF3·OEt2-promoted oxygen transfer reaction of N-aryl-α,ß-unsaturated nitrones to prepare various N,O-difluoroboron ß-ketoiminates in good yields ranging from 24% to 87%. Control experiments revealed that the enaminone was the vital intermediate for the formation of N,O-difluoroboron ß-ketoiminates, and iron(III) combined with BF3·OEt2 played as cocatalyst to promote the oxygen transfer reaction through intramolecular cyclization and N-O bond cleavage. More importantly, an estrone-derived N,O-difluoroboron ß-ketoiminate was easily prepared in 40% yield from estrone in four steps.

Combined Dextran-Graft-Polyacrylamide/Zinc Oxide Nanocarrier for Effective Anticancer Therapy in vitro.

Introduction: Cancer chemotherapy faces two major challenges - high toxicity of active substances and tumor resistance to drugs. Low toxic nanocarriers in combination with anticancer agents can significantly increase the effectiveness of therapy. Modern advances in nanotechnology make it easy to create materials with the necessary physical and chemical properties. Methods: Two hybrid nanosystems of dextran-polyacrylamide/ zinc oxide nanoparticles (D-PAA/ZnO NPs) were synthesized in aqueous solution with zinc sulphate (D-PAA/ZnO NPs (SO42-)) and zinc acetate (D-PAA/ZnO NPs (-OAc)). The light absorption, fluorescence, dynamic light scattering and transmission electron microscopy for nanocomposite characterization were used. MTT, neutral red uptake and scratch assays were selected as fibroblasts cytotoxicity assays. Cytotoxicity was tested in vitro for normal fibroblasts, MAEC, prostate (LNCaP, PC-3, DU-145) and breast (MDA-MB-231, MCF-7) cancer cells lines. Immunocytochemical methods were used for detection of Ki-67, p53, Bcl-2, Bax, e-cadherin, N-cadherin and CD44 expression. Acridine orange was used to detect morphological changes in cells. Results: The radius of ZnO NPs (SO42-) was 1.5 nm and ZnO NPs (-OAc) was 2 nm. The nanosystems were low-toxic to fibroblasts, MAEC. Cells in the last stages of apoptosis with the formation of apoptotic bodies were detected for all investigated cancer cell lines. Proapoptotic proteins expression in cancer cells indicates an apoptotic death. Increased expression of E-cadherin and N-cadherin was registered for cancer cells line LNCaP, PC-3, DU-145 and MCF-7 after 48 h incubation with D-PAA/ZnO NPs (SO42-). Conclusion: The nanosystems were low-toxic to fibroblasts, MAEC. The D-PAA/ZnO NPs nanosystem synthesized using zinc sulphate demonstrates high cytotoxicity due to destruction of various types of cancer cells in vitro and potentially increases adhesion between cells. Thus, our findings indicate the selective cytotoxicity of D-PAA/ZnO NPs against cancer cells and can be potentially used for cancer treatment.