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Enzymatic Strategy for the Resolution of New 1-Hydroxymethyl Tetrahydro- β-carboline Derivatives in Batch and Continuous-Flow Systems.
- Source :
- ChemistryOpen; Jun2016, Vol. 5 Issue 3, p254-260, 7p
- Publication Year :
- 2016
-
Abstract
- Many alkaloids containing a tetrahydro- β-carboline skeleton have well-known therapeutic effects, leading to increased interest in the synthesis of these natural products. Enantiomers of N-Boc-protected 1-hydroxymethyl-1,2,3,4-tetrahydro- β-carboline [(±)- 7], 1-hydroxymethyl-6-methoxy-1,2,3,4-tetrahydro- β-carboline [(±)- 8], and 1-hydroxymethyl-6-fluoro-1,2,3,4-tetrahydro- β-carboline [(±)- 9] were prepared through enzymecatalyzed asymmetric acylation of their primary hydroxyl group. The preliminary experiments were performed in a continuous-flow system, while the preparative-scale resolutions were done as batch reactions. Excellent enantioselectivities ( E>200) were obtained with Candida antarctica lipase B (CAL-B) and acetic anhydride in toluene at 60 °C. The recovered alcohols and the produced esters were obtained with high enantiomeric excess values ( ee≥96 %). The O-acylated enantiomers [( S)- 10-( S)- 12)] were transformed into the corresponding amino alcohols [( S)- 7-( S)- 9)] with methanolysis. Microwave-assisted Boc removals were also performed and resulted in the corresponding compounds ( R)- 4-( R)- 6 and ( S)- 4-( S)- 6 without a drop in the enantiomeric excess values ( ee≥96 %). [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 21911363
- Volume :
- 5
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- ChemistryOpen
- Publication Type :
- Academic Journal
- Accession number :
- 116344201
- Full Text :
- https://doi.org/10.1002/open.201500203