A metal-free cross-coupling of enamines and electron-deficient amines through oxidative C(sp(2))-N bond formation has been realized by using TBAI as catalyst and TBHP as oxidant. This novel strategy allows for an efficient organocatalytic synthesis of the synthetically useful diaminoalkene derivatives and is highlighted by appealing features such as readily available of the starting materials, wide substrate scope and transition-metal-free characteristics.
An exclusive trans-aminocarboxylation and oxoaminocarboxylation of diarylalkynes were realized through hypervalent iodine-mediated cascade annulations under metal-free conditions, leading to divergent assembly of fused or spiro polycyclic heterocycles with a dosage of the hypervalent iodine oxidant. The mechanisms for the formation of both products are proposed.
Encapsulation of therapeutic molecules into nanocarrier is an extensively explored strategy to treat cancer more effectively. In this study, pH-responsive targeting dual-agent delivery nanoparticles were prepared, into which hydrophilic doxorubicin hydrochloride (DOX) and hydrophobic curcumin (CUR) were entrapped. Tyrosine (Tyr) was grafted onto poly(aspartic acid) (PASP) to produce PASP-Tyr, the following reaction between hyaluronic acid (HA) and ethylenediamine (EDA) modified PASP-Tyr formed the nanocarrier HA-EDA-PASP-Tyr (HEPT), and the loading capacity was up to 50.9 ± 4.3% for CUR and 26.0 ± 1.9% for DOX. The spherical HEPT with the mean particle size of 142.9 ± 11.4 nm expanded and deformed into petaloid pattern with an increased size of about 2 µm when triggered by the acidic microenvironment. In vitro anticancer activity evaluation revealed that the co-loaded (DOX+CUR)@HEPT nanoparticles presented higher cytotoxicity against HCT-116 cells compared with that of the free combination of (DOX+CUR). Confocal laser scanning microscopy observation indicated that HEPT carrier promoted cellular uptake of drugs by means of active targeting capacity of HA ligand. With high loading capacity and tailored carrier structure, the nanoparticles formulations may offer a new strategy for cancer treatment.
The trans‐aminocarboxylation of alkynes is performed following a two‐pot two‐step reaction procedure while delivering fused polyheterocyclic compounds in high yields.
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