55974-69-1Relevant articles and documents
A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones
Hosono, Kazumi,Kodama, Shintaro,Nomoto, Akihiro,Ochi, Takanori,Ogawa, Akiya,Tabuchi, Akihiro,Yamamoto, Yuki,Yamazaki, Kento
, p. 2906 - 2914 (2022/01/12)
A simple and efficient method for α-brominating lactones that affords α-bromolactones under mild conditions using tetraalkylammonium hydroxide (R4N) as a base was developed. Lactones are ring-opened with Br2 and a substoichiometric amount of PBr3, leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (H2O/CHCl3) containing R4N afforded α-bromo lactones in good yields. This method can be applied at the 10 mmol scale using simple operations. α-Bromo-δ-valerolactone, which is extremely reactive and difficult to isolate, could be isolated and stored in a freezer for about one week using the developed method. Optimizing the solvent for environmentally friendly large-scale syntheses revealed that methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to facilitate the industrial use of α-bromolactones as important intermediates.
A 2,5-di-hydroxy valeric acid DELTA lactone synthetic method
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Paragraph 0006; 0014-0017, (2017/03/14)
The invention aims to provide a synthesizing method of 2,5-dihydroxyvaleric acid delta lactone. The synthesizing method comprises an improved and economical method for synthesizing lactone derivatives and the like. Importantly, the synthesizing method is suitable for high-selectivity low-cost mass production.
Synthetic studies towards the core structure of nakadomarin a by a thioamide-based strategy
Chavda, Jai K.,Procopiou, Panayiotis A.,Horton, Peter N.,Coles, Simon J.,Porter, Michael J.
, p. 129 - 139 (2014/01/06)
The tricyclic BCD substructure of the marine natural product nakadomarin A has been synthesised. The strategy utilised a key carbon-carbon bond-forming reaction between a furan and an N-acyliminium ion derived from a secondary thiolactam. In addition, a novel three-component coupling reaction between a thioamide, an allylic bromide and an isocyanate, leading to the establishment of two new stereogenic centres, is reported. Two key steps in a projected total synthesis of nakadomarin A have been realised by using the unique chemistry of thioamides. Formation of the carbocyclic B ring can be effected by nucleophilic attack of a furan on a thiolactam-derived iminium ion, and the key quaternary centre can be established by a novel three-component coupling reaction.
Natural product biosynthesis inspired concise and stereoselective synthesis of benzopyrones and related scaffolds
Baskar, Baburaj,Dakas, Pierre-Yves,Kumar, Kamal
, p. 1988 - 1991 (2011/06/25)
A natural product biosynthesis-inspired strategy to explore biologically relevant chemical space is presented. A phosphine-catalyzed cascade and stereoselective annulation provides a common tricyclic benzopyrone intermediate that was efficiently transformed into diverse and related naturally occurring scaffolds
A stereoselective cyclisation cascade mediated by SmI2-H 2O: Synthetic studies towards stolonidiol
Baker, Thomas M.,Sloan, Lisa A.,Choudhury, Lokman H.,Murai, Masahito,Procter, David J.
experimental part, p. 1246 - 1261 (2010/11/02)
A cascade reaction involving sequential conjugate reduction, stereoselective aldol cyclisation and chemoselective lactone reduction mediated by SmI2-H2O provides access to a cyclopentanol bearing two vicinal quaternary stereocentres with good stereocontrol. The functionalised cyclopentanol product has been converted to a key intermediate in ongoing asymmetric studies towards stolonidiol.
Aluminium(III) Coordination to Hydroxy Carboxylates: the Influence of Hydroxy Substituents Enabling Tridentate Binding
Best, Wayne M.,Harrowfield, Jack M.,Shand, Todd M.,Stick, Robert V.
, p. 2023 - 2032 (2007/10/02)
Potentiometric evalution of the interaction between aluminium(III) and the hydroxy carboxylates 3-deoxy-D-ribo-hexonate (L1H) and 2,5-dihydroxypentanoate (L2H) provided evidence for the formation of 1:1 complexes only, though with the ligand being present in singly, doubly and quadruply deprotonated forms in the hexonate complexes, and in singly, doubly and triply deprotonated forms in those of the pentanoate.At 298 K in aqueous media, I = 0.1 (NaCl), equilibrium quotient values obtained through use of the programs PKAS and BEST were: -log(1)->+>/1H>) (or pKa(L1H)) = 3.58+/-0.03; log(1)2+>/3+>1)->) = 1.97+/-0.03; log(-1L1)+>+>/1)2+>) = -2.83+/-0.05; log(-3L1)->+>2/-1L1)+>) = -9.17+/-0.08; -log(2)->+>(2H>) (or pKa(L2H)) = 3.92+/-0.03; log(2)2+>/3+>2)->) = 2-04+/-0.03; log(-1L2)+>+>/2)2+>) = -3.14+/-0.06; log(-2L2>+>/-1L2)+>) = -2.25+/-0.09.The very close similarity of the results for 3-deoxy-D-ribo-hexonate (3-deoxygluconate) and those known for D(+)-gluconate has led to the suggestion that the complexes of the quadruply deprotonated ligands may involve trialkoxo coordination through the C1, C5 and C6 substituents.
The Conformational Behaviour of 10-Substituted Spirodecanes
Wolff, J. Jens,Frenking, Gernot,Harms, Klaus
, p. 551 - 561 (2007/10/02)
The conformational behaviour of 10-X-substituted 1,4-dioxa- and 1,4,6-trioxaspirodecanes 1-4 has been studied by 13C-, 19F- and 1H-NMR spectroscopy.Two X-ray analyses of (2a,e) are presented, and their implications to cleavage reactions of chiral acetals are discussed.Participation of twist boat forms in the conformeric equilibrium of at least 1c has been made plausible by observing 13C, 19F-NMR coupling constants.The ratios of axial to equatorial conformers in 1-4 have been calculated by molecular mechanics.
