• Bis-(cinchona alkaloid) ligands (which are generally the better catalysts) catalyze the formation of diols of high enantiopurity from a very broad range of olefins. (sigmaaldrich.com)
  • A significant phylogenetic signal was found for the content of two out of four major Cinchona alkaloids (quinine and cinchonidine) and their total content. (frontiersin.org)
  • Cinchonidine sulphate, (C 19 H 22 N 2 O) 2 ,H 2 SO 4 ,3H 2 O, is the salt of a base found in cinchona bark. (henriettes-herb.com)
  • Synthetically modified cinchona alkaloids are typical chiral organocatalysts used in asymmetric PTC. (sigmaaldrich.com)
  • Cinchona alkaloids and their derivatives have proven to catalyze an astonishing array of enantioselective transformations, providing access to chiral products of high enantiopurity. (sigmaaldrich.com)
  • In connection with our ongoing project that deals with the catalytic potential of the cinchona-alkaloid-derived amides,[17-19] we became interested in examining the reaction of allenoates with imines in the presence of a chiral tertiary amine catalyst. (docme.ru)
  • The medicinal value of Cinchona bark was first discovered in Loxa (now Loja, Ecuador) in the seventeenth century by Jesuit monks, and soon exports of different varieties of Cinchona pubescens Vahl (red bark) from South America to Europe were reaching half a million kilograms bark per year ( Roersch van der Hoogte and Pieters, 2015 ). (frontiersin.org)
  • In an attempt to further improve catalyst enantioselectivities, Jew and Park linked two cinchona alkaloid moieties via spacer units. (sigmaaldrich.com)
  • In particular, the cinchona alkaloids catalyze many useful processes with high enantioselectivities. (sigmaaldrich.com)
  • Climatic and soil parameters were characterized and bark samples were analyzed for content of the four major alkaloids using HPLC-UV to explore the utility of evolutionary history (phylogeny) in determining variation within species of these compounds under natural conditions. (frontiersin.org)
  • At the present time (1917) thirty or forty more or less clearly defined species of Cinchona are recognized. (henriettes-herb.com)
  • Cinchona alkaloids can be used as bases to deprotonate substrates with relatively acidic protons forming a contact ion pair between the resulting anion and protonated amine. (sigmaaldrich.com)
  • Subsequently, these cinchona alkaloids were used for the osmium-catalyzed asymmetric aminohydroxylation of olefins. (sigmaaldrich.com)
  • Cinchona is classified in the division Magnoliophyta Magnoliophyta , division of the plant kingdom consisting of those organisms commonly called the flowering plants, or angiosperms. (thefreedictionary.com)
  • Despite a ban on export, Europeans sent cinchona seeds and seedlings to Java and India, where plantations were established. (thefreedictionary.com)
  • Of all of these probably but four with their cultivated hybrids yield the Cinchona Bark of commerce. (henriettes-herb.com)
  • The literature of the cinchona hybrids is hopelessly confused by the same name being frequently used by different authorities for the different hybrids and the one hybrid having various names. (henriettes-herb.com)
  • Import could not meet demand, and a quest began for the most productive source of Cinchona trees to establish plantations by the British, Dutch, and French empires. (frontiersin.org)
  • A clade of high alkaloid producing trees was identified that spanned a narrow range of altitudes, from 1,100 to 1,350 m. (frontiersin.org)
  • So successful were the Dutch and English in transplanting cinchona to Java and India that until World War II these countries, especially Java, grew practically the entire commercial supply. (thefreedictionary.com)
  • Four years later, Linne proposed a new name, Cinchona , in honor of the Countess of Chinchon, who first made the bark known in Europe. (henriettes-herb.com)
  • As a result of selection, the alkaloid content in the bark was raised from 2-2.5 percent to 16 percent. (thefreedictionary.com)