935-38-6Relevant academic research and scientific papers
Driving an equilibrium acetalization to completion in the presence of water
Minakawa, Maki,Yamada, Yoichi M. A.,Uozumi, Yasuhiro
, p. 36864 - 36867 (2014/11/08)
Formation of an acetal from a carbonyl substrate by condensation with an alcohol is a classical reversible equilibrium reaction in which the water formed must be removed to drive the reaction to completion. A new method has been developed for acetalization of carbonyl substrates by diols in the presence of water. Complexation of poly(4-styrenesulfonic acid) with poly(4-vinylpyridine) generates a catalytic membrane of polymeric acid at the interface between two parallel laminar flows in a microchannel of a microflow reactor. The catalytic membrane provides a permeable barrier between the organic layer and water-containing layer in the reaction, and permits discharge of water to the outlet of the microreactor to complete the acetalization. Condensation of a variety of carbonyl substrates with diols proceeded in the presence of water in the microflow device to give the corresponding acetals in yields of up to 97% for residence times of 19 to 38 s. the Partner Organisations 2014.
Stereoselective synthesis of tertiary ethers through geometric control of highly substituted oxocarbenium ions
Liu, Lei,Floreancig, Paul E.
supporting information; experimental part, p. 5894 - 5897 (2010/12/18)
Fully substituted, fully controlled I The geometries of 1,1-disubstituted oxocarbenium ions and the conformations of oxocarbenium ions that contain a tertiary stereocenter can be predicted based on simple models. These models have been applied to highly stereoselective syntheses of tetrahydropyran derivatives that contain tertiary ethers (see scheme; RL, Rs, and RN represent large, small, and nucleophilic groups, respectively). (Figure Presented)
Chemoselective and chemospecific protection and deprotection of a carbonyl group using polystyrene divinylbenzene sulfonic acid
Verma, Sanjeev K.,Sathe, Manisha,Kaushik
experimental part, p. 1701 - 1707 (2010/07/15)
Chemospecific protection of one carbonyl group of two identical carbonyls of 2,2-dialkyl-1,3-cyclohexanedione and chemoselective protection of aliphatic or aromatic carbonyls in the presence of conjugated carbonyl compounds using cross-linked polystyrene divinyl benzene sulfonic acid (SPS) as a heterogeneous catalyst has been demonstrated. Copyright
A remarkable iodine-catalyzed protection of carbonyl compounds
Banik, Bimal K.,Chapa, Marin,Marquez, Jocabed,Cardona, Magda
, p. 2341 - 2343 (2007/10/03)
We report here a remarkably simple molecular iodine-catalyzed protection method for various carbonyl compounds as ketals in a general reaction. The iodine-catalyzed reaction of mandelic acid and lactic acid with several aldehydes has furnished a highly diastereoselective synthesis of cis and trans dioxolanones.
1,3-Dioxolanes from carbonyl compounds over zeolite HSZ-360 as a reusable, heterogeneous catalyst
Ballini, Roberto,Bosica, Giovanna,Frullanti, Bettina,Maggi, Raimondo,Sartori, Giovanni,Schroer, Frank
, p. 1615 - 1618 (2007/10/03)
Carbonyl compounds are converted, in good yields, into their 1,3-dioxolanes over zeolite HSZ-360, as a new reusable catalyst. Good chemoselectivity is also observed.
Photochemical Reaction of Benzene-1,2,4,5-tetracarbonitrile with the Ketals of Cyclic and Bicyclic Ketones
Mella, Mariella,Freccero, Mauro,Albini, Angelo
, p. 1047 - 1052 (2007/10/02)
The radical cations of the ethylene ketals of some cyclic and bicyclic ketones are generated by single electron transfer to excited benzene-1,2,4,5-tetracarbonitrile (TCB).Their fragmentation yields 1,5- and 1,6-distonic radical cations, which add to TCB(-.) to give alkyl>benzenetricarbonitriles.The reduction of the radical center occurs only to a small extent, and is enhanced in the presence of dodecylmercaptan, in the case of hindered radicals.The reaction of the camphor ethylene ketal (both alkylation of TCB and reduction) occurs with total diastereoselectivity at the reacting radical center.
Sulfonated charcoal, a mild and efficient reagent for the preparation of cyclic acetals, dithioacetals and benzodioxepines
Patney, Haris K.
, p. 413 - 416 (2007/10/02)
1,3-Dioxolanes, 1,3-Ditholanes and 1,5-dihydro-3H-2,4-benzodioxepines were prepared by the direct condensation of carbonyl compounds with 1,2-ethanediol, 1,2-ethanedithiol or 1,2-benzenedimethanol under the heterogeneous conditions of sulfonated charcoal catalyst.
N-(arylmethyl)-2-(or -4)-cyanopyridinium hexafluoroantimonates as new useful catalysts for acetalization of carbonyl compounds
Lee,Lee,Takata,Endo
, p. 368 - 370 (2007/10/02)
Carbonyl compounds 1 were converted to the corresponding 1,3-dioxolanes 2 and 1,3-dioxanes 4 with ethylene glycol and 2,2-dimethyl-1,3-propandiol, respectively, in the presence of 1-3 mol% of N-(benzyl, 4-methylbenzyl or 4-methoxybenzyl)-2(or -4)cyanopyridinium hexafluoroantimonates 3. The catalyst 3d was also effective for the tetrahydropyranylation.
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.
REGIO- AND STEREOSELECTIVE CONTROL IN THE ALKYLATION OF 1-ALKOXY-1,4-CYCLOHEXADIENES BY THE CHIRAL AUXILIARY APPROACH. ENANTIOSELECTIVE SYNTHESIS OF PRECURSORS FOR CIS-HYDRINDANES.
Stanssens, Dirk,Keukeleire, Denis De,Vandewalle, Maurits
, p. 547 - 560 (2007/10/02)
A method is described for the regio- and diastereoselective alkylation of optically active 1-alkoxy-1,4-cyclohexadienes.Reaction conditions were optimised for substrates 4a with the per-O-methyl-β-D-glucopyranosyl group as chiral auxiliary.In the methylat
