93379-07-8Relevant articles and documents
Continuous enzymatic stirred tank reactor cascade with unconventional medium yielding high concentrations of (S)-2-hydroxyphenyl propanone and its derivatives
Glaser, Juliane,Oeggl, Reinhard,Rother, D?rte,von Lieres, Eric
, p. 7886 - 7897 (2021/12/27)
The implementation of biocatalysis in flow chemistry offers synergistic synthesis advantages in line with green chemistry principles. Yet, the conversion of high substrate concentrations is in many cases hindered by insolubility issues or substrate toxicity. Here, the continuous synthesis of (S)-2-hydroxyphenyl propanone (2-HPP) from inexpensive benzaldehyde and acetaldehyde in a methyltert-butyl ether based organic reaction environment, namely micro-aqueous reaction system, has been established. Kinetic parameters of the applied whole cell catalyst were identified to design a continuous process for (S)-2-HPP synthesis. This revealed a necessity to distribute acetaldehyde over a spatial coordinate to remain below a toxic concentration threshold. Hence, three continuous stirred tank reactors (cSTR) were conjugated in a technical cascade with an additional influx of acetaldehyde into each unit. The catalytic behaviour of this reaction setup was described based on mass balances and a kinetic model. Enzyme deactivation was described by a novel staged model and compared to a simple generic model. The optimized continuous setup yielded 190 mM (S)-HPP with an ee > 98% over 8 h. The product was easily recovered from the organic reaction environment by crystallization with an isolated yield of 68% and a purity of >99%. Further, the substrate range of the applied catalystPseudomonas putidabenzoylformate decarboxylase variant L461A was analysed. This revealed numerous halogenated, methoxylated and nitro-derivatives inortho,meta, andparaposition, which can in principle be gained by the established process. As an example, the applied cSTR concept was transferred top-methoxy benzaldehyde with good results even without further optimization.
Biocatalytic route to chiral acyloins: P450-catalyzed regio- and enantioselective α-hydroxylation of ketones
Agudo, Rubén,Roiban, Gheorghe-Doru,Lonsdale, Richard,Ilie, Adriana,Reetz, Manfred T.
, p. 950 - 956 (2015/01/30)
P450-BM3 and mutants of this monooxygenase generated by directed evolution are excellent catalysts for the oxidative α-hydroxylation of ketones with formation of chiral acyloins with high regioselectivity (up to 99%) and enantioselectivity (up to 99% ee). This constitutes a new route to a class of chiral compounds that are useful intermediates in the synthesis of many kinds of biologically active compounds.
Studies towards the stereoselective α-hydroxylation of flavanones. Biosynthetic significance
Border, Zola-Michele,Marais, Charlene,Bezuidenhoudt, Barend C. B.,Steenkamp, Jacobus A.
, p. 122 - 130 (2008/04/11)
The enolates of various propiophenones, chromanones, and also analogues of naturally occurring flavanones were stereoselectively hydroxylated at the ?-position, by employing commercially available enantiopure oxaziridines, to afford the desired ?-hydroxylated target molecules in good to exceptional stereoselectivities and in moderate to good chemical yields. A mechanistic rationale is presented to account for the stereoselectivities achieved. These in vitro results were tentatively related to the stereoselective biosynthesis of enantio-enriched dihydroflavonols while questions were raised about the authenticity of certain natural compounds. CSIRO 2008.
