Nonprotecting Group Synthesis of a Phospholipase C Activatable Probe with an Azo-Free Quencher

The near-infrared fluorescent activatable smart probe Pyro-phosphatidylethanolamine (PtdEtn)-QSY was synthesized and observed to selectively fluoresce in the presence of phosphatidylcholine-specific phospholipase C (PC-PLC). PC-PLC is an important biological target as it is known to be upregulated in a variety of cancers, including triple negative breast cancer. Pyro-PtdEtn-QSY features a QSY21 quenching moiety instead of the Black Hole Quencher-3 (BHQ-3) used previously because the latter contains an azo bond, which could lead to biological instability

Tungsten-Mediated Selective Ring Opening of Vinylcyclopropanes

The complexes TpW­(NO)­(PMe₃)­(L), where L = 2<i>H</i>-phenol, 2<i>H</i>-<i>p</i>-cresol, 2<i>H</i>-5,6,7,8-tetrahydro-2-naphthol, 2<i>H</i>-<i><i>N,N</i>-</i>dimethylanilinium were cyclopropanated using Simmons–Smith conditions. Cyclopropanated derivatives of 2<i>H</i>-<i>N,N</i>-dimethylanilinium were selectively ring-opened with HOTf/MeCN to form allylic species, which could be coupled with various nucleophiles. The nucleophilic addition occurs <i>anti</i> to the metal fragment, as determined by X-ray crystallography. Moreover, the cyclopropane ring opening occurs regioselectively, owing to the stabilization of the allylic cation by the metal fragment. The resulting ligands can, in some cases, be removed from the metal by oxidative decomplexation using ceric ammonium nitrate (CAN)

Tungsten-Mediated Selective Ring Opening of Vinylcyclopropanes

The complexes TpW­(NO)­(PMe₃)­(L), where L = 2<i>H</i>-phenol, 2<i>H</i>-<i>p</i>-cresol, 2<i>H</i>-5,6,7,8-tetrahydro-2-naphthol, 2<i>H</i>-<i><i>N,N</i>-</i>dimethylanilinium were cyclopropanated using Simmons–Smith conditions. Cyclopropanated derivatives of 2<i>H</i>-<i>N,N</i>-dimethylanilinium were selectively ring-opened with HOTf/MeCN to form allylic species, which could be coupled with various nucleophiles. The nucleophilic addition occurs <i>anti</i> to the metal fragment, as determined by X-ray crystallography. Moreover, the cyclopropane ring opening occurs regioselectively, owing to the stabilization of the allylic cation by the metal fragment. The resulting ligands can, in some cases, be removed from the metal by oxidative decomplexation using ceric ammonium nitrate (CAN)