Saumya Dabral

  • RWTH Aachen
  • Templergraben 55
  • 52056 Aachen
  • Germany

 

My SuBiCat publications:

 

2017  Organocatalytic Chemoselective Primary Alcohol Oxidation and Subsequent Cleavage of Lignin Model Compounds and Lignin

S. Dabral, J. G. Hernández, P. C. J. Kamer, C. Bolm, Chemsuschem, Volume 10, Issue 13 July 10, 2017 Pages 2707–2713

A one-pot two-step degradation of lignin β-O-4 model compounds initiated by preferred oxidation of the primary over the secondary hydroxyl groups with a TEMPO/DAIB system has been developed [TEMPO=2,2,6,6-tetramethylpiperidine-N-oxyl, DAIB=(diacetoxy)iodobenzene]. The oxidised products are then cleaved by proline-catalysed retro-aldol reactions. This degradation methodology produces simple aromatics in good yields from lignin model compounds at room temperature with an extension to organosolv beech-wood lignin (L1) resulting in known cleavage products.

 

2017  Mechanochemical Lignin-Mediated Strecker Reaction

S. Dabral, M. Turberg, A. Wanninger, C. Bolm, J. G. Hernández, Molecules 2017, 22(1), 146;

A mechanochemical Strecker reaction involving a wide range of aldehydes (aromatic, heteroaromatic and aliphatic), amines, and KCN afforded a library of α-aminonitriles upon mechanical activation. This multicomponent process was efficiently activated by lignocellulosic biomass as additives. Particularly, commercially available Kraft lignin was found to be the best activator for the addition of cyanide to the in situ formed imines. A comparative study of the 31P-NMR (Nuclear Magnetic Resonance) along with IR (Infrared) data analysis for the Kraft lignin and methylated Kraft lignin samples ascertained the importance of the free hydroxyl groups in the activation of the mechanochemical reaction. The solvent-free mechanochemical Strecker reaction was then coupled with a lactamization process leading to the formation of the N-benzylphthalimide (5a) and the isoindolinone derivative 6a

 

2017  Selective enzymatic esterification of lignin model compounds in the ball mill

U. Weißbach, S. Dabral, L. Konnert, C. Bolm, J. G. Hernández, Beilstein J. Org. Chem. 2017, 13, 1788–1795

 

2015  Base-catalysed cleavage of lignin β-O-4 model compounds in dimethyl carbonate

Saumya Dabral, Jakob Mottweiler, Torsten Rinescha and Carsten Bolm, Green Chem. 2015, 17(11), 4908-4912

A base-catalysed transformation and cleavage of lignin β-O-4 model compounds in dimethyl carbonate is reported. The reaction system consists of readily available bases and inexpensive dimethyl carbonate as a solvent and reagent, affording methoxy benzene or 2-aryloxyvinyl benzene derivatives in good to very good yields. The applicability of the system for the bond cleavage in an organosolv lignin sample was demonstrated.

My SuBiCat poster presentations:

 

Base catalysed cleavage of β-O-4 lignin model compounds in dimethyl carbonate

7th New Year Symposium at the Institute of Organic Chemistry, RWTH Aachen, Germany, January 9th 2015

 

E-mail: Saumya.Dabral@oc.rwth-aachen.de

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