Asymmetric construction of six vicinal stereogenic centers on hexahydroxanthones via organocatalytic one-pot reactions.

Inspired by the chemistry and biology of hexahydroxanthones, herein we report an organocatalytic Michael-Michael-Aldol-decarboxylation reaction that provides efficient access to biologically interesting fully substituted hexahydroxanthones bearing six contiguous stereogenic centers from readily accessible materials in acceptable yields (up to 63%) and excellent stereoselectivities (up to 10 : 1 dr and >99% ee). In other words, the reaction efficiently produces three chemical bonds and up to six vicinal stereogenic centers in a one-pot operation. In particular, to our knowledge, this is an asymmetric organocatalytic strategy enabling the first construction of six vicinal stereogenic centers on non-spirocyclic hexahydroxanthone frameworks.

Organocatalytic Reaction of Chromone-Oxindole Synthon: Access to Chromanone-Based Spirocyclohexaneoxindoles with Five Adjacent Stereocenters.

An efficient strategy for stereo-controlled synthesis of potential biological and structurally complex chromanone-based spirocyclohexaneoxindoles via an organocatalytic domino formal double Michael cycloaddition of bifunctional chromone-oxindole synthons and nitroolefins is reported. These products possessing five adjacent stereocenters including one spiro quaternary carbon center, were smoothly afforded in up to 85% yield, >99% ee, and >20:1 dr. This strategy benefits from the intramolecular nature of the second Michael reaction step, through counterbalancing the lower electrophilicity of these unactivated chromones to facilitate the reaction.

Stereocontrolled Synthesis of Bispirooxindole-Based Hexahydroxanthones with Five Contiguous Stereocenters.

A bifunctional oxindole-chromone synthon 1 directed tandem reaction is developed, serving as a fruitful strategy for facile access to optically active hexahydroxanthones 3 bearing two spirooxindoles with five contiguous stereocenters. All of the bispirooxindole-based hexahydroxanthones 3 are smoothly obtained with up to 91% yield, >20:1 dr, and >99% ee. Biological evaluation of selected compounds 3 revealed that they exerted good cytotoxic effects on human K562, A549, and PC-3 cells.

[Isolation, induction and differentiation of human blood-derived endothelia progenitor cells].

OBJECTIVE: To determine the biological traits and optimal condition for the induction and differentiation of endothelial progenitor cells from peripheral blood in healthy adults. METHODS: Mononuclear cells isolated from peripheral blood of healthy adults were cultured in M199 medium supplemented with VEGF, bFGF, IGF-1, and EGF. The appearing time of cell clusters or spindle-shaped cells was recorded respectively. Attached spindle-shaped cells were detached and labeled with a series of antibodies against blood vessel endothelial-specific markers. RESULTS: Attached spindle-like cells appeared 4 days after the culture, cell clusters were observed at 5 to 8 days, and cord-like structure was formed by 10th day. These cells expressed endothelial-specific markers. CONCLUSION: Endothelial progenitors cells were derived from mononuclear cells of peripheral blood, which can be induced into endothelial cells at specific conditions.

Isolation, induction and differentiation of human blood-derived endothelia progenitor cells / 中南大学学报(医学版)

OBJECTIVE@#To determine the biological traits and optimal condition for the induction and differentiation of endothelial progenitor cells from peripheral blood in healthy adults.@*METHODS@#Mononuclear cells isolated from peripheral blood of healthy adults were cultured in M199 medium supplemented with VEGF, bFGF, IGF-1, and EGF. The appearing time of cell clusters or spindle-shaped cells was recorded respectively. Attached spindle-shaped cells were detached and labeled with a series of antibodies against blood vessel endothelial-specific markers.@*RESULTS@#Attached spindle-like cells appeared 4 days after the culture, cell clusters were observed at 5 to 8 days, and cord-like structure was formed by 10th day. These cells expressed endothelial-specific markers.@*CONCLUSION@#Endothelial progenitors cells were derived from mononuclear cells of peripheral blood, which can be induced into endothelial cells at specific conditions.