Novel A-ring analogs of the hormone 1α,25-dihydroxyvitamin D3: synthesis and preliminary biological evaluation
作者:Gary H. Posner、S.H. Tony Lee、Hyung Jin Kim、Sara Peleg、Patrick Dolan、Thomas W. Kensler
DOI:10.1016/j.bmc.2005.02.005
日期:2005.4
Prepared from a commercial prostaglandin building block, novel vitamin D3 analogs with a contracted five-membered A-ring were designed and synthesized to mimic the A-ring diol structure of the natural hormone 1alpha,25-dihydroxyvitamin D3. Prepared from commercial 1,4-cyclohexanedione, a structurally simplified analog was designed and synthesized in which a suitably oriented primary allylic hydroxyl
SOLVENT EFFECTS IN REACTIONS OF DIKETONES WITH WITTIG AND WITTIG-HORNER REAGENTS
作者:Sheila Mawaziny、Amal M. Lawny
DOI:10.1080/10426500008046614
日期:2000.8.1
Abstract In a series of reactions between Wittig or Wittig-Horner (Wadsworth-Emmons) reagents and diketones it was found that out of the five solvents tested, for the Wittig reagents, namely dichloromethane, toluene, ethanol, dimethylformamide, and pyridine, only pyridine had a significant effect on the Z:E ratio of isomeric products, percent Z isomer being increased. In contrast to the Wittig reagents