Preparation of Polyacetoxytropones and Polyhydroxytropolones by Acetolysis and Hydrolysis of Halotroponoids by Acetyl Trifluoroacetate with Exhaustive Displacement of Halogens on the Tropone Ring. Predominant Formation of Reductive Acetolysates from Fully-Substituted Tropones
acetic acid-mediated reduction of intermediary formed acetoxy-p-tropoquinone equivalents. A couple of 2,7-unsubstituted 3,4-diacetoxytropones were deduced to have cyclized 1,3-dioxole structures, 2-acetoxy-2-methyl-5H-cyclohepta-1,3-dioxol-5-ones. An acetolysis of the brominated 5-isopropyltropolones furnished an acetylated by-product, 2,3,7-triacetoxy-5-(1,1-dimethyl-2-oxopropyl)tropone, which might be
Highly enantioselective hydroamination to six-membered rings by heterobimetallic catalysts
作者:Lenard Hussein、Nibadita Purkait、Mustafa Biyikal、Eugenia Tausch、Peter W. Roesky、Siegfried Blechert
DOI:10.1039/c3cc48874h
日期:——
New bimetallic Zn/Zr salen-type systems were employed as catalysts in the asymmetric intramolecular hydroamination reaction. High enantioselectivity for the formation of piperidines of up to 98% ee were observed.
Reactions of Tetrasulfur Tetranitride with Tropolone and Its Several Halogeno Derivatives. Preparations of 4<i>H</i>-Cyclohepta[<i>c</i>][1,2,5]thiadiazol-4-ones, 6<i>H</i>-Cyclohepta[<i>c</i>][1,2,5]thiadiazol-6-one, and 7<i>H</i>-Cyclohepta-[1,2-<i>c</i>:3,4-<i>c</i>′]bis[1,2,5]thiadiazol-7-ones
The reactions of tropolones with tetrasulfurtetranitride gave 4H-cyclohepta[c][1,2,5]thiadiazol-4-ones, 6H-cyclohepta[c][1,2,5]thiadiazol-6-one, and 7H-cyclohepta[1,2-c: 3,4-c′]bis[1,2,5]thiadiazol-7-ones (9–56% yields) in one step. The yields of the products were not improved so much under high pressure and by the addition of a radical initiator.
α-Hydroxytropolones: A New Class of Potent Inhibitors of Inositol Monophosphatase and Other Bimetallic Enzymes
作者:Serge R. Piettre、Axel Ganzhorn、Jan Hoflack、Khalid Islam、Jean-Marie Hornsperger
DOI:10.1021/ja9634278
日期:1997.4.1
Mono- and polyhydroxytropolones are potent competitiveinhibitors of inositolmonophosphatase. Modeling studies indicate that this inhibition occurs most probably through a novel mode of action involving the chelation of the two magnesium ions in the active site. This is consistent with experimental data. Inhibition occurs when at least three oxygen atoms are present on the seven-membered ring, and
Zur Tautomerie vonO-Acyl- undO-Alkylidenpropandinitril-Gruppen in Trihalotropolonen und Dithiotropolonen
作者:Klaus Hartke、Michaela Sauerbier
DOI:10.1002/ardp.19923250806
日期:——
Thallium(I)‐trihalotropolonate 4bilden mit Benzoylchlorid (5) die O‐Benzoyl‐trihalotropolone 6und mit Chlorbenzylidenpropandinitril (7) die O‐Benzylidenpropandinitril‐trihalotropolone 8. Beide zeigen eine schnelle Wanderung der O‐Substituenten zwischen den Sauerstoffatomen, für die sehr ähnliche ΔG#‐ und k25‐Werte aus NMR‐Messungen ermittelt wurden. Natriumdithiotropolonat (10) läßt sich zu den thermolabilen