Synthesis of nitrogenated lignin-derived compounds and reactivity with laccases. Study of their application in mild chemoenzymatic oxidative processes

The chemical synthesis of a series of nitrogenated lignin-derived compounds, their reactivity with laccases and further application in mild oxidative processes are here disclosed.

Novel chemoenzymatic oxidation of amines into oximes based on hydrolase-catalysed peracid formation

The efficient transformation of benzylamines into the corresponding oximes has been described by means of a chemoenzymatic process.

Catalytic Promiscuity of Transaminases: Preparation of Enantioenriched β-Fluoroamines by Formal Tandem Hydrodefluorination/Deamination

Transaminases are valuable enzymes for industrial biocatalysis and enable the preparation of optically pure amines. For these transformations they require either an amine donor (amination of ketones) or an amine acceptor (deamination of racemic amines). Herein transaminases are shown to react with aromatic β-fluoroamines, thus leading to simultaneous enantioselective dehalogenation and deamination to form the corresponding acetophenone derivatives in the absence of an amine acceptor. A series of racemic β-fluoroamines was resolved in a kinetic resolution by tandem hydrodefluorination/deamination, thus giving the corresponding amines with up to greater than 99 % ee. This protocol is the first example of exploiting the catalytic promiscuity of transaminases as a tool for novel transformations.

Deracemisation of profenol core by combining laccase/TEMPO-mediated oxidation and alcohol dehydrogenase-catalysed dynamic kinetic resolution

A one-pot two-step chemoenzymatic protocol to deracemise a profen-like derivative has been designed.

Synthesis of vitamin D3 analogues with A-ring modifications to directly measure vitamin D levels in biological samples

C-3-substituted 25-hydroxyvitamin D3 analogues were synthesized as tools to directly measure levels of vitamin D in biological samples. The strategy involves vinyloxycarbonylation of the 3β-hydroxy group and formation of a carbamate bond with a hydroxyl or amino group at the end of the alkyl chain. Biotinylated conjugates of synthesized derivatives were generated to be linked with vitamin D binding protein (DBP). The spacer group present in the alkyl chain is important in the binding of antibodies to the analogue-DBP complex. When compared to 25-hydroxyvitamin D3-DBP, the binding of some antibodies to the analogue-DBP complex of the 25-hydroxyvitamin D3 derivative 10 that posses an 8-aminoctyl alkyl chain is significantly reduced, but this analogue displaced [26,27-(3)H]-25-hydroxyvitamin D3 from DBP. In contrast, the 8-hydroxyoctyl alkyl chain analogue 9 showed less displacement.