Palladium-Catalyzed Carbonylative Cyclization of β-Bromo-α,β-unsaturated Carboxylic Acids Leading to Maleic Anhydrides
作者:Chan Cho、Yeon Bae
DOI:10.1055/s-0033-1339309
日期:——
β-Bromo-α,β-unsaturatedcarboxylicacids are carbonylativelycyclized under carbon monoxide pressure in acetic acid in the presence of a catalytic amount of a palladium catalyst along with a base to give the corresponding maleic anhydrides in high yields.
Chaetomellic anhydride A, a potent inhibitor of Ras proteinfarnesyltransferase, was synthesized in 61% yield over four steps from methyl propionate. The synthesis features palladium-catalyzed carboxylation reaction under Cacchi conditions, efficiently incorporating carbon monoxide generated in situ from acetic formic anhydride into β-carbomethoxyalkenyl triflate, and giving rise to the maleic anhydride
[EN] IMPROVED THERMOPLASTIC HYDROPHILIC ADHESIVE COMPOSITIONS FOR ATTACHMENT ON DRY AND WET SURFACES AND WITH INCREASED WATER ADHESION STABILITY<br/>[FR] COMPOSITIONS ADHESIVES HYDROPHILES THERMOPLASTIQUES AMELIOREES DESTINEES A ADHERER A DES SURFACES SECHES ET HUMIDES ET PRESENTANT UNE MEILLEURE STABILITE D'ADHERENCE A L'EAU
申请人:PROCTER & GAMBLE
公开号:WO2004016704A1
公开(公告)日:2004-02-26
The present invention relates to thermoplastic hydrophilic adhesive compositions having an increased adhesion capability and stability on moist or wet surfaces. The adhesive compositions comprise a thermoplastic hydrophilic homogeneous polymeric matrix having selected liquid absorption capacity, liquid absorption rate, and rheology. The adhesive compositions of the present invention are particularly suitable as topical adhesives for skin adhesion of articles such as disposable waste management articles, disposable absorbent articles, and personal care articles.
The Profound Effect of the Ring Size in the Electrocyclic Opening of Cyclobutene-Fused Bicyclic Systems
作者:Michael J. Ralph、David C. Harrowven、Steven Gaulier、Sean Ng、Kevin I. Booker-Milburn
DOI:10.1002/anie.201410115
日期:2015.1.26
Fused cyclobutenes, prepared by the photocycloaddition of propargyl alcohols to cyclic anhydride chromophores, undergo facile thermochemical ringopening to fused γ‐lactones. The size of the fused ring profoundly influences the temperature that is required to facilitate the ringopening (from 50 °C to 180 °C) and the nature of the product that is formed. Our studies provide new insights into the mechanistic