56669-96-6Relevant articles and documents
Repurposing an Aldolase for the Chemoenzymatic Synthesis of Substituted Quinolines
Fansher, Douglas J.,Granger, Richard,Kaur, Satinderpal,Palmer, David R. J.
, p. 6939 - 6943 (2021)
Quinoline derivatives are important natural products and pharmaceuticals, but their synthesis can be challenging due to poor yields, harsh reaction conditions, and instability of starting materials. Here we report the chemoenzymatic synthesis of quinaldic acids under mild conditions using an aldolase, trans-o-hydroxybenzylidenepyruvate hydratase-aldolase (NahE, or HBPA). A series of 2-aminobenzaldehydes derived from reduction of the corresponding nitro analogue were reacted with pyruvate in the presence of NahE to give substituted quinolines in up to 93% isolated yield. This reaction differs from the aldol condensation catalyzed by NahE in vivo, instead resembling the heterocycle formation catalyzed by its homologue, dihydrodipicolinate synthase.
A highly effective one-pot synthesis of quinolines from o-nitroarylcarbaldehydes
Li, An-Hu,Ahmed, Eilaf,Chen, Xin,Cox, Matthew,Crew, Andrew P.,Dong, Han-Qing,Jin, Meizhong,Ma, Lifu,Panicker, Bijoy,Siu, Kam W.,Steinig, Arno G.,Stolz, Kathryn M.,Tavares, Paula A. R.,Volk, Brian,Weng, Qinghua,Werner, Doug,Mulvihill, Mark J.
, p. 61 - 64 (2008/03/14)
A simple and an efficient one-pot quinoline synthesis using inexpensive and readily available reagents was proposed. The solids were removed by filtration and the filtrate was treated with ketone and powdered KOH. The o-Nitroarylcarbaldehydes were reduced to aminocarbaldehydes with iron in the presence of catalytic HCl and subsequently condensed in situ with aldehydes or ketones to form mono- or di-substituted quinolines in high yields. The method can be used to prepare 2,3-disubstituted quinolines. A mixture of isomers was generated when an unsymmetrical ketone was used, which proved to be easily separable by silica gel column chromatography. The one-pot procedure is mild enough to allow a phenyl-substituted α,β-unsaturated ketone for using as a reactant under basic conditions in refluxing ethanol without significant competition from 1,4-Michael addition. The method provides efficient means to synthesize biologically active natural and unnatural quinoline-derived compounds.
