- Indium(III) triflate catalysed transacetalisation reactions of diols and triols under solvent-free conditions
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Acyclic acetals and ketals undergo transacetalisation in the presence of catalytic quantities of indium(III) triflate (In(OTf)3) and diols or triols under solvent-free conditions to generate the corresponding cyclic acetals and ketals in excellent yield. The methodology has been further developed to encompass a tandem acetalisation-acetal exchange protocol, which provides a facile and high yielding route to cyclic ketals from unreactive ketones under very mild reaction conditions.
- Smith, Brendan M.,Kubczyk, Tomasz M.,Graham, Andrew E.
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experimental part
p. 7775 - 7781
(2012/09/21)
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- Indium triflate mediated tandem acetalisation-acetal exchange reactions under solvent-free conditions
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Acyclic acetals and ketals undergo exchange reactions in the presence of catalytic quantities of indium(III) triflate and diols to generate the corresponding cyclic acetals and ketals in excellent yield. The protocol is rapid, employs mild conditions and can be adapted to employ solvent-free reaction conditions. We have further developed this methodology to encompass a tandem acetalisation-acetal exchange protocol which provides facile access to cyclic ketals from unreactive ketones also under very mild, solvent-free reaction conditions.
- Smith, Brendan M.,Graham, Andrew E.
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experimental part
p. 6281 - 6283
(2011/12/14)
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- Quantitative analysis of solvent effects in highly aqueous media. Application of the SWAG procedures and a critical appraisal of the additivity principle
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This paper describes a study on medium effects of 25 monohydric and polyhydric alcohols on the neutral hydrolysis of 1-benzoyl-3-phenyl-1,2,4-triazole in highly aqueous media. Dependences of pseudo-first-order rate constants on molality of added alcohol are quantitatively analyzed in terms of pairwise Gibbs energy interaction parameters for initial state and transition state. Additivity of pairwise group interaction parameters (SWAG procedure) is applied, and the validity of additivity is critically examined. Excellent additivity is observed in series of monohydric alcohols and vicinal diols. In series of polyhydric alcohols, group contributions to the observed rate effects, as expressed in pairwise group interaction parameters, are, however, strongly dependent on the position of hydroxyl groups in the alcohol. This (apparent) nonadditivity behavior is discussed in terms of the hydration characteristics of the cosolvents. The importance of hydration shell overlap in determining medium effects is supported by kinetic data in ternary 1-propanol-urea-water mixtures.
- Blokzijl,Engberts,Blandamer
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p. 1197 - 1201
(2007/10/02)
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- Synthese d'acetals cycliques dans des conditions douces; Applications a l'acetalisation du chloramphenicol
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Acetalization of 1-2 and 1-3 diols, even as sterically crowded as chloramphenicol, by carbonyl derivatives with substituents of various sizes has been performed at room temperature under mild conditions, by using heterogeneous catalysis (sulfonated polystyrene) in the presence of molecular sieves.Several new acetals of chloramphenicol have thus been obtained in good yields, isolated and characterized.
- Meslard, J. C.,Subira, F.,Vairon, J. P.,Guy, A.,Garreau, R.
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