129968-03-2Relevant articles and documents
Monoamine oxidase (MAO-N) catalyzed deracemization of tetrahydro-β- carbolines: Substrate dependent switch in enantioselectivity
Ghislieri, Diego,Houghton, Deborah,Green, Anthony P.,Willies, Simon C.,Turner, Nicholas J.
, p. 2869 - 2872 (2013)
The tetrahydro-β-carboline (THBC) ring system is an important structural motif found in a large number of bioactive alkaloid natural products. Herein we report a broadly applicable method for the synthesis of enantiomerically pure β-carbolines via a deracemization procedure employing the D9 and D11 variants of monoamine oxidase from Aspergillus niger (MAO-N) in combination with a nonselective chemical reducing agent. Biotransformations were performed on a preparative scale, leading to the synthesis of optically enriched products in excellent enantiomeric excess (e.e.; up to 99%) and isolated yield (up to 93%). Interestingly, a switch in enantioselectivity associated with the MAO-N variants is observed as the nature of the C-1 substituent of the THBC is varied. Molecular modeling provided an explanation for this observation and highlighted key active site residues which were modified, resulting in an increase in (R)-selectivity associated with the enzyme. These results provide insight into the factors which influence the selectivity of the MAO-N variants, and may offer a platform for future directed evolution projects aimed toward the challenge of engineering (R)-selective amine oxidase biocatalysts.
Carboxyl-Mediated Pictet-Spengler Reaction. Direct Synthesis of 1,2,3,4-Tetrahydro-β-carbolines from Tryptamine-2-carboxylic Acids
Narayanan, Krishnaswamy,Schindler, Liesl,Cook, James M.
, p. 359 - 365 (2007/10/02)
The Pictet-Spengler condensation of various tryptamine-2-carboxylic acids 9a-f with carbonyl compounds in benzene/dioxane/trifluoroacetic acid (Table I) with simultaneous loss of carbon dioxide afforded directly the corresponding 1,2,3,4-tetrahydro-β-carb
