Continuous‐flow multistep synthesis is combined with quasi‐continuous final‐product purification to produce pure products from crude reaction mixtures. In the nucleophilic aromatic substitution of 2,4‐difluoronitrobenzene with morpholine followed by a heterogeneous catalytic hydrogenation, the desired monosubstituted product can be continuously separated from the co‐ and by‐products in a purity of over 99 % by coupling a flow reactor sequence to a multiple dual‐mode (MDM) centrifugal partition chromatography (CPC) device. This purification technique has many advantages over HPLC, such as higher resolution and no need for column replacement or silica recycling, and it does not suffer from irreversible adsorption.

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Continuous-flowm ultistep synthesis is combined with quasi-continuous final-product purification to produce pure products from crude reaction mixtures.I nt he nucleophilic aromatic substitution of 2,4-difluoronitrobenzene with morpholine followed by aheterogeneous catalytic hydrogenation, the desired monosubstituted product can be continuously separated from the co-and by-products in apurity of over 99 % by coupling af low reactor sequence to am ultiple dual-mode (MDM) centrifugal partition chromatography (CPC) device. This purification technique has many advantages over HPLC, such as higher resolution and no need for column replacement or silica recycling,a nd it does not suffer from irreversible adsorption.

Starting from racemic naringenin ((±)-1), a mixture of dracocephin A stereoisomers 6-(2”-pyrrolidinone-5”-yl)naringenin (±)-2a–d and its regioisomer, dracocephin B 8-(2”-pyrrolidinone-5”-yl)naringenin (±)-3a–d originally isolated from Dracocephalum rupestre, have been synthesized in a one-pot reaction. The separation of 2a–d and 3a–d was achieved by preparative HPLC. The four stereoisomers of each natural product were separated by analytical chiral HPLC and their absolute configuration was studied by the combination of HPLC–ECD measurements and TDDFT–ECD calculations. The synthesized flavonoid alkaloids were further characterized by physicochemical and in vitro pharmacological studies.

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