PdPb-Catalyzed decarboxylation of proline to pyrrolidine: Highly selective formation of a biobased amine in water
Amino acids have huge potential as platform chemicals in the biobased industry. Pd-catalyzed decarboxylation is a very promising route for the valorization of these natural compounds derived from protein waste or fermentation. We report that the highly abundant and nonessential amino acid L-proline is very reactive in the Pd-catalyzed decarboxylation. Full conversions are obtained with Pd/C and different Pd/MeOx catalysts; this allowed the identification of the different side reactions and the mapping of the reaction network. Due to the high reactivity of pyrrolidine, the selectivity for pyrrolidine was initially low. By carefully modifying Pd/ZrO2 with Pb in a controlled mannervia two incipient wetness impregnation stepsthe selectivity increased remarkably. Finally, a thorough investigation of the reaction parameters resulted in an increased activity of this modified catalyst and an even further enhanced selectivity under a low H2 pressure of 4 bar at 235 °C in water. This results in a very selective and sustainable production route for the highly interesting pyrrolidine.
Verduyckt, Jasper,Van Hoof, Maarten,De Schouwer, Free,Wolberg, Marike,Kurttepeli, Mert,Eloy, Pierre,Gaigneaux, Eric M.,Bals, Sara,Kirschhock, Christine E.A.,De Vos, Dirk E.
p. 7303 - 7310
(2018/05/23)
Heterocomplexation of a chiral dipeptide and quantitative enantiomeric enrichment of nonracemic 1,1′-Bi-2-naphthol
(Chemical Equation Presented) Heterocomplexation of a chiral host to a racemic guest has been discovered. A cyclic dipeptide generated from (S)-proline alkyl ester undergoes an achiroselective complexation to both the enantiomers of racemic BINOL in benzene to yield a crystalline heterocomplex bearing the solvent molecules. However, complexation crystallization does not occur between the diptide and either enantiomer of BINOL under similar conditions. The difference in complexation behavior has been successfully applied in the enantiomeric enrichment of nonracemic BINOLs, and almost quantitative separation of the excess enantiomer from racemic BINOL was achieved.
Shan, Zixing,Xiong, Ying,Yi, Jing,Hu, Xiaoyun
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p. 9158 - 9160
(2009/04/04)
Efficient preparation of proline N-carboxyanhydride using polymer-supported bases
A procedure for the preparation of proline N-carboxyanhydride in high yield and purity is described using polymer-supported tertiary amines. The polymer-supported amine can be recycled with a basic wash and filtration of the resin. The procedure facilitates the access to the efficient preparation of the polyproline polymer with potential therapeutic interest.
Gulin, Oscar P.,Rabanal, Francesc,Giralt, Ernest
p. 5385 - 5388
(2007/10/03)
Synthesis and Novel Properties of N-Phosphoryl Peptides
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Ma, Xiao-bo,Zhao, Yu-fen
p. 4005 - 4008
(2007/10/02)
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