72486-22-7Relevant academic research and scientific papers
Synthesis of Furo[3,2-c]benzopyrans via an Intramolecular [4 + 2] Cycloaddition Reaction of o-Quinonemethides
Zhao, Li-Ming,Zhang, Ai-Li,Gao, Hua-Shuai,Zhang, Jie-Huan
, p. 10353 - 10358 (2015)
An intramolecular [4 + 2] cycloaddition reaction of o-quinonemethides generated from salicylaldehydes and α-prenylated alcohols is described. In the presence of a catalytic amount of benzenesulfonic acid (BSA), the reaction proceeded smoothly in EtOH to afford furo[3,2-c]benzopyrans through a three-bond forming process in moderate to excellent yields with high diastereoselectivity. This reaction provides a simple and straightforward protocol to efficiently construct furo[3,2-c]benzopyran skeletons. A possible mechanism involving hemiacetal formation/hetero-Diels-Alder reaction is proposed to rationalize the observed results.
On the antibiotic activity of oxazolomycin
Bagwell, Claire L.,Moloney, Mark G.,Thompson, Amber L.
body text, p. 4081 - 4086 (2009/04/07)
Structural analysis of oxazolomycin and simpler fragments containing a common 3-hydroxy-2,2-dimethylpropanamide moiety has indicated that a U-shaped conformation is preferred, in some cases stabilised by hydrogen bonding between the N-H and O-H residues, as shown by a combination of molecular modelling, NMR spectroscopic and single crystal X-ray analysis. A direct synthesis of this unit has been established via the opening of β-lactones by a range of amines, and their antibacterial activity been shown to vary with the hydrophobic character of the substituents.
Lithium hydroxide as base in the Wittig reaction. A simple method for olefin synthesis
Antonioletti,Bonadies,Ciammaichella,Viglianti
, p. 4644 - 4648 (2008/09/20)
A mild and practical procedure for the Wittig olefination, promoted by lithium hydroxide and triphenylbenzyl phosphonium bromide, has been set up for the synthesis of stilbenes and styrenes. The experimental conditions allow aromatic, heteroaromatic, unsaturated and saturated aliphatic aldehydes to give final products in good yields.
Cyclialkylation of arylalkyl epoxides with solid acid catalysts
Elings, Jacob A.,Downing, Roger S.,Sheldon, Roger A.
, p. 837 - 846 (2007/10/03)
Solid acids, such as zeolites and clays, catalyse the intramolecular hydroxyalkylation (cyclialkylation) of several arylalkyl epoxides in moderate to excellent conversions and selectivities. The use of solid acids in these cyclialkylations provides a cleaner, better alternative to conventional Lewis and Bronsted acids, enabling a more facile workup of reaction mixtures and, in several cases, better selectivities.
Regioselective palladium-catalysed coupling reactions of vinyl chlorides with carbon nucleophiles
Reetz, Manfred T.,Wanninger, Klaus,Hermes, Marcus
, p. 535 - 536 (2007/10/03)
Vinyl chlorides bearing methyl groups in the 2-position can be activated catalytically by palladium(0)-complexes of 1,4-bis(dicyclohexylphosphino)butane, the process involving vinyl-allyl isomerization via CH-activation followed by nucleophilic attack of
A direct synthesis of olefins by reaction of carbonyl compounds with lithio derivatives of 2-[alkyl- or (2'-alkenyl)- or benzyl-sulfonyl]-benzothiazoles
Baudin,Hareau,Julia,Ruel
, p. 1175 - 1178 (2007/10/02)
During the title reaction, the lithium alkoxides formed as intermediates undergo an intramolecular addition to the neighboring C = N group followed an S to O benzothiazole transfer and simultaneous extrusion of sulfur dioxide and ejection of 2(3H)-benzothiazolone anion.
An improved variant of the Julia olefin synthesis: Reductive elimination of β-hydroxy imidazolyl sulfones by samarium diiodide
Kende,Mendoza
, p. 7105 - 7108 (2007/10/02)
The reductive elimination reaction of β-hydroxy imidazolyl sulfones 1 to afford the corresponding olefins can be accomplished under mild conditions and in good yields using SmI2, offering a convenient modification of the Julia olefin synthesis.
PALLADIUM(0) CATALYZED REACTIONS OF 1,4-EPIPEROXIDES
Suzuki, Masaaki,Oda, Yoshihisa,Hamanaka, Nobuyuki,Noyori, Ryoji
, p. 517 - 535 (2007/10/02)
The Pd(PPh3)4 catalyzed reaction of 2,3-saturated and 2,3-unsaturated 1,4-epiperoxides proceeds by courses markedly different from those of the previously reported transition metal catalyses.The Pd(0)-promoted reaction of 2,3-saturated epiperoxides gives the corresponding 4-hydroxy ketones and 1,4-diols as the major products.From 2,3-dedihydroepiperoxides are formed the corresponding 4-hydroxy enones, syn-1,2;3,4-diepoxides, and 1,4-diols.The results are interpreted in terms of competing Pd(0)/Pd(II) exchange mechanisms.Exposure of prostaglandin (PG) H2 methyl esterto Pd(PPh3)4 produces a mixture of methyl esters of PGD2, PGE2, PGF2α, and (5Z,8E,10E,12S)-12-hydroxy-5,8,10-heptadecatrienoic acid.
An E-Selective 1,3-Diene Synthesis from Moderated Ylides and Aldehydes
Vedejs, E.,Fang, Huang Wen
, p. 210 - 212 (2007/10/02)
The synthesis of E-1,3-dienes by the Wittig reaction of aldehydes and ylides is described.
Anwendungen der Phasentransfer-Katalyse 17. Wittig-Reaktionen in verschiedenen Zweiphasen-Systemen
Dehmlow, Eckehard V.,Barahona-Naranjo, Simon
, p. 1748 - 1762 (2007/10/02)
EINE vergleichende Untersuchung von Wittig-Reaktionen unter Phasentransfer-Katalyse (PTC) bei verschiedenen Bedingungen wurde durchgefuehrt.Es erwies sich als unnoetig, ausser den Phosphoniumsalzen einen PTC-Katalysator zu verwenden.Mechanistische Konsequenzen dieses Befundes werden diskutiert.Als ein besonders geeignetes Basensystem stellte sich Kalium-tert-butoxid in Benzol heraus.Erstmals gelang die Umzetzung von Ketonen und aliphatischen Aldehyden.Einige sehr hohe Literaturausbeuten von PTC-Wittig-Reaktionen konnten unter praeparativen Bedingungen nicht reproduziert werden.
