4339-94-0Relevant academic research and scientific papers
The Influence of Anchoring Substitution in 1,3-Amino Alcohols on the Rate and Mechanism of Esterification by Acetylimidazole and by p-Nitrophenyl Acetate
Steels, Ivan,Clercq, Pierre J. De,Maskill, Howard
, p. 294 - 295 (1993)
Enforced intramolecular hydrogen bonding in 2-tert-butyl-3-(N,N-dimethylamino)propan-1-ol is shown by the competitive alcoholysis of p-nitrophenyl acetate and 1-acetylimidazole in acetonitrile, and by the corresponding second-order rate constants and activation parameters, to influenece both the rate and the mechanism of catalysed acyl transfer.
Structure-reactivity relationships in the rate of esterification by acetylimidazole: The influence of the second hydroxy group and of the length of the N-ω-hydroxy-n-alkyl chain in 3-(N-methyl, N-ω-hydroxy-n-alkyl)ammo-2-tert-butylpropan-1-ols
Madder, Annemieke,De Clercq, Pierre J.,Maskill, Howard
, p. 851 - 852 (1997)
Enforced intramolecular hydrogen bonding facilitates intramolecular general base catalysis in the acetylation of a family of α,ω-amino alcohols by acetylimidazole, and the site of acetylation when there are two hydroxy groups is determined by the relative ease of intramolecular hydrogen bonding rather than by intermolecular steric effects.
Lipase-mediated selective acetylation of primary alcohols in ethyl acetate
de Souza, Ernane C.,Romero-Ortega, Moises,Olivo, Horacio F.
supporting information, p. 287 - 290 (2017/12/29)
An environmental friendly process to selectively acetylate primary alcohols was demonstrated. The esterification process consists of treatment of a primary alcohol in the presence of immobilized C. antarctica lipase (Novozyme-435) in ethyl acetate at room temperature. Primary alcohols were acetylated in the presence of secondary alcohols and phenols.
Stepwise Approach toward First Generation Nonenzymatic Hydrolases
Madder, Annemieke,De Clercq, Pierre J.,Declercq, Jean-Paul
, p. 2548 - 2559 (2007/10/03)
The synthesis and reactivity study of a first generation serine protease mimic is described. Central in the design stands the possibility of stabilization of the transition state by an amino triol such as 8t. En route to 8t, a series of amino alcohols (4-8) was obtained, the reactivity of which was studied toward esterification by acetylimidazole (AcIm) and by p-nitro-2,2,2-trifluoroacetanilide (PNTFA). Interesting reactivity differences were observed between the cis- and the trans-series, especially between 7c and 7t (AcIm), and between 8c and 8t (PNTFA). In both cases the results are explained by invoking extra stabilization of the tetrahedral oxyanion.
Mechanism of esterification of 1,3-dimethylamino alcohols by N-acetylimidazole in acetonitrile and the influence of alkyl and geminal dialkyl substitution upon the rate
Madder, Annemieke,Sebastian, Sonny,Van Haver, Dirk,De Clercq, Pierre J.,Maskill, Howard
, p. 2787 - 2793 (2007/10/03)
3-(Dimethylamino)propan-1-ol and seven derivatives with alkyl substituents at the 2-position have been prepared by conventional methods, and second-order rate constants for their esterification by N-acetylimidazole in acetonitrile have been measured under pseudo-first-order conditions both by 1H NMR spectroscopy at a single temperature (23°C) and by a UV spectroscopic method over the temperature range 25-65°C. Evidence is presented that the intermolecular esterifications proceed via an initial rate-determining intramolecular general base catalysed formation of a cyclic tetrahedral intermediate. Effective molarities compared with the third-order reactions of simpler alcohols with acetylimidazole catalysed by triethylamine are estimated to be 13-14 mol dm-3, but alkyl substitution at the 2-position of the amino alcohol has only a modest effect upon reaction rates. All reactions have substantial negative entropies of activation and only modest enthalpies of activation as expected for concerted bimolecular reactions with highly ordered transition structures. Three structurally related carbocyclic amino alcohols constitute a short isokinetic series with the isokinetic temperature very close to the experimental range. Along this series, decreasing enthalpies of activation are almost exactly balanced in their contributions to the overall free energy of activation near room temperature by increasingly negative entropies of activation.
Gas-Phase Elimination Kinetics of (Dimethylamino)alkyl Acetates. The Ion-Pair Mechanism through Neighboring Group Participation.
Chuchani, Gabriel,Rotinov, Alexandra,Dominguez, Rosa M.,Gonzalez, Neil
, p. 4157 - 4160 (2007/10/02)
The gas-phase elimination kinetics of some amino esters and a keto acetate have been studied in the temperature region of 260.0-411.5 deg C and in the pressure range of 21.5-170.0 torr.These eliminations, in vessels seasoned with allyl bromide, are predominantly unimolecular and homogenous and obey a first order rate law.The rate coefficients for the reactions are expressible by the following Arrhenius equations: for 3-(dimethylamino)-1-propyl acetate (1), log k1 (s-1) = (12.97 +/- 0.20) - (202.1 +/- 2.5) kJ mol-1 (2.303RT)-1; for 4-(dimethylamino)-1-butyl acetate (4), log k1 (s-1) = (11.91 +/- 0.43) - (163.5 +/- 4.8) kJ mol-1 (2.303 RT)-1; for 4-oxo-1-pentyl acetate (7), log k1 (s-1) = (12.77 +/- 0.36) - (202.8 +/- 4.6) kJ mol-1 (2.303RT)-1.The presence of the (CH3)2N group in these acetates appears to provide anchimeric assistance in the elimination; methyl acetate and the corresponding heterocyclic products arise from an intimate ion-pair mechanism.The CH3CO substituent is believed to influence the pyrolysis rate of 5-acetoxy-2-pentanone by a weak steric acceleration.
