848821-58-9Relevant articles and documents
Preparation method of duloxetine
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, (2021/09/26)
To the method, 1 - naphthol and 3 - (2 - thienyl) -2 - acrolein serve as starting materials, and (S)-3 - (1 - naphthyloxy) -3 - (2 - thienyl) propanal is obtained through addition reaction under the action of a catalyst. The raw materials are cheap and easily available, and 1 - fluoronaphthalene which is expensive is not needed. Sodium hydride and operation are tedious, the cost is low, the process operation is safe and convenient, the three wastes are small in generation amount, and green and environment-friendly. The reaction atom economy is high, the reaction selectivity of each step is high, the side reaction is small, the optical purity and yield of the target product are high, and the green industrial production is facilitated.
Basicities and Nucleophilicities of Pyrrolidines and Imidazolidinones Used as Organocatalysts
An, Feng,Maji, Biplab,Min, Elizabeth,Ofial, Armin R.,Mayr, Herbert
supporting information, p. 1526 - 1547 (2020/02/04)
The Br?nsted basicities pKaH (i.e., pKa of the conjugate acids) of 32 pyrrolidines and imidazolidinones, commonly used in organocatalytic reactions, have been determined photometrically in acetonitrile solution using CH acids as indicators. Most investigated pyrrolidines have basicities in the range 16 aH aH aH 12.6) and the 2-imidazoliummethyl-substituted pyrrolidine A21 (pKaH 11.1) are outside the typical range for pyrrolidines with basicities comparable to those of imidazolidinones. Kinetics of the reactions of these 32 organocatalysts with benzhydrylium ions (Ar2CH+) and structurally related quinone methides, common reference electrophiles for quantifying nucleophilic reactivities, have been measured photometrically. Most reactions followed second-order kinetics, first order in amine and first order in electrophile. More complex kinetics were observed for the reactions of imidazolidinones and several pyrrolidines carrying bulky 2-substituents, due to reversibility of the initial attack of the amines at the electrophiles followed by rate-determining deprotonation of the intermediate ammonium ions. In the presence of 2,4,6-collidine or 2,6-di-tert-butyl-4-methyl-pyridine, the deprotonation of the initial adducts became faster, which allowed the rate of the attack of the amines at the electrophiles to be determined. The resulting second-order rate constants k2 followed the correlation log?k2(20 °C) = sN(N + E), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by the two solvent-dependent parameters N and sN. In this way, the organocatalysts A1-A32 were integrated in our comprehensive nucleophilicity scale, which compares n-, -, and σ-nucleophiles. The nucleophilic reactivities of the title compounds correlate only poorly with their Br?nsted basicities.
(S)-1,1-diphenylprolinol trimethylsilyl ether
Boeckman, Robert K.,Tusch, Douglas J.,Biegasiewicz, Kyle F.
, p. 309 - 319 (2016/08/23)
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