Ruthenium-Catalyzed Tandem Cross-Metathesis/Wittig Olefination: Generation of Conjugated Dienoic Esters from Terminal Olefins
摘要:
In the presence of ruthenium-based olefin metathesis catalysts and triphenylphosphine, alpha,beta-unsaturated aldehydes can be olefinated with diazoacetates. This ruthenium-catalyzed transformation has been employed in tandem with olefin cross-metathesis to convert terminal olefins into 1,3-dienoic esters in a single operation.
Development of Amidine-Based Sphingosine Kinase 1 Nanomolar Inhibitors and Reduction of Sphingosine 1-Phosphate in Human Leukemia Cells
摘要:
Sphingosine 1-phosphate (S1P) is a bioactive lipid that has been identified as an accelerant of cancer progression. The sphingosine kinases (SphKs) are the sole producers of S1P, and thus, SphK inhibitors may prove effective in cancer mitigation and chemosensitization. Of the two SphKs, SphK1 overexpression has been observed in a myriad of cancer cell lines and tissues and has been recognized as the presumptive target over that of the poorly characterized SphK2. Herein, we present the design and synthesis of amidine-based nanomolar SphK1 subtype-selective inhibitors. A homology model of SphK1, trained with this library of amidine inhibitors, was then used to predict the activity of additional, more potent, inhibitors. Lastly, select amidine inhibitors were validated in human leukemia U937 cells, where they significantly reduced endogenous S1P levels at nanomolar concentrations.
Imidamide (amidine) analogs that can inhibit the activity of sphingosine kinase 1 and sphingosine kinase 2 (SphK1 & SphK2) are provided. The compounds can prevent angiogenesis in tumors.
Ring-Conformer Effects of the Cyclopropyl Group: First Use of trans-(2R,3R)-Cyclopropanecarbaldehydes as Electrophiles in Diastereoselective Baylis-Hillman Reaction
trans-(2R,3R)-Cyclopropanecarbaldehydes are used as novel electrophiles in the Baylis-Hillman reaction to afford adducts in good yields (75-85%) and diastereoselectivities (60-90%).
Preparation of Aliphatic Ketones through a Ruthenium-Catalyzed Tandem Cross-Metathesis/Allylic Alcohol Isomerization
作者:David Finnegan、Benjamin A. Seigal、Marc L. Snapper
DOI:10.1021/ol060918g
日期:2006.6.1
shown to be effective catalysts for cross-metatheses of allylic alcohols with cyclic and acyclic olefins, as well as isomerization of the resulting allylic alcohols to alkyl ketones. The net result of this new tandem methodology is a single-flask process that provides highly functionalized, ketone-containing products from simple allylic alcohol precursors. [reaction: see text]
Imidamide (amidine) analogs that can inhibit the activity of sphingosine kinase 1 and sphingosine kinase 2 (SphK1 & SphK2) are provided. The compounds can prevent angiogenesis in tumors.