Synthesis of novel spiro[cyclopropane-pyrrolizin] derivatives via Mg-mediated conjugate addition of bromoform

Substrate-oriented selectivity in the Mg-mediated conjugate addition of bromoform to electron-deficient alkenes

The Mg-mediated conjugate addition of bromoform to a variety of electron-deficient alkenes has been investigated. In the case of nitrodienes and dibenzylideneacetones, tribromomethylated products were isolated, whereas spiro-cyclopropanated products were obtained with cyclic dibenzylideneketones and 3-olefinic oxindoles. The spiro-cyclopropyl ketones derived from cyclic dibenzylideneketones were successfully transformed into fused furans via the Cloke-Wilson rearrangement.

Synthesis of 2-(1-Oxo-2,3-Dihydro-1H-Pyrrolizin-2-yl)-2-(Aryl)Acetonitrile Derivatives Via Michael Addition of Trimethylsilyl Cyanide

Several 2-aryl-2-(1-oxo-2,3-dihydro-1 H-pyrrolizin-2-yl)acetonitrile derivatives were synthesised by Michael addition of ( E)-2-arylidene-2,3-dihydro-1 H-pyrrolizin-1-ones with trimethylsilyl cyanide in the presence of tetrabutylammonium fluoride in moderate yields. The structures of all of the products were fully characterised by NMR, IR and high-resolution mass spectrometry, together with X-ray crystallographic analysis.

Spectroscopic analyses on interaction of bovine serum albumin with novel spiro[cyclopropane-pyrrolizin]

The interaction between novel spiro[cyclopropane-pyrrolizin] (NSCP) and bovine serum albumin (BSA) was analyzed by fluorescence and ultraviolet-visible (UV-Vis) spectroscopy at 298 K, 304 K and 310 K under simulative physiological conditions. The results showed that NSCP can effectively quench the intrinsic fluorescence of BSA via static quenching. The binding constants, binding sites of NSCP with BSA were calculated. Hydrogen binds and van der Waals force played a major role in stabilizing the complex and the binding reaction were spontaneous. According to the Förster non-radiation energy transfer theory, the average binding distances between NSCP and BSA were obtained. What is more, the synchronous fluorescence spectra indicated that the conformation of BSA has been changed.

Synthesis of α-tribromomethylamines via Mg-mediated addition of bromoform to imines

Mg-mediated addition of bromoform to electron deficient imines such as N-sulfonylimines affords α-tribromomethylated N-sulfonylamines in good to excellent yields. The procedure could be further simplified by transforming the imine precursors, α-sulfonyl-N-tosyl- and Boc-amines, in one pot to the corresponding α-tribromomethyl derivatives. Facile removal of the Boc protecting group in nearly quantitative yield and a silver carbonate mediated monodebromination have also been demonstrated.