PubMed · 11289698
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R Brommage, H Vafai. 2000. Rapid embedding protocol for visualizing bone mineral and matrix.. https://doi.org/10.1007/s002230001187
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Benzaldehyde lyase (BAL; E.C. 4.1.2.38) from Pseudomonas fluorescens Biovar I catalyzes the reversible formation of benzoins from aromatic aldehydes, and, moreover, the coupling of aromatic with aliphatic aldehydes yielding derivatives of (R)-2-hydroxy-1-phenyl- propan-1-one (R)-HPPs), which are important chiral building blocks. In this paper, we report on the development of a reactor system that allows the selective production of substituted (R)-HPP-derivatives. The reaction systems yielding (R)-1-(3-chloro-phenyl)-2-hydroxy- propan-1-one, (R)-2-hydroxy-3-methoxy-1-(4-methoxy-phenyl)-propan-1-one, and (R)-2-hydroxy-3,3-dimethoxy-1-phenyl-propan-1-one were investigated. A kinetic model optimized by batch experiments was developed, for the description of both batch and continuously operated reactors. This model was used to describe the HPP production in a continuously operated enzyme membrane reactor. The reactor type used combines the advantages of high conversion and excellent selectivity with high space-time yields and total turnover numbers of up to ttn=43,000. Products were obtained in high yield on a gram scale.
The THz spectra of amino acids after application of spots of acetone were measured. The 0.6 THz band was commonly observed in many amino acids that formed the intra-molecular salt structure. The band can be attributed to the interaction vibration from the common structural configuration of amino acids and acetone molecules. The evidence suggests that the vibration between the amino acids with intra-molecular salt structure and acetone has a peak at 0.6 THz. A model of the interaction vibration of acetone and the functional groups of amino acids is proposed.
Enolate generated from O-(tetrahydropyran-2-yl)hydroxyacetone under thermodynamically controlled conditions (1.3 equiv of NaH, THF, 0 degrees C to rt) was allylated at the carbon bearing the protected hydroxy group with very high regioselectively. When tert-BuOH, equivalent to the excessive portion of initially added NaH, was introduced into the mixture followed by addition of aldehyde, aldol reaction took place on the methyl group to give 1-substituted 4-hydroxy-(1E),6-heptadien-3-one in acceptable yields after acidic treatment of the mixture for dehydration and deprotection. Introducing a chiral auxiliary protecting group into hydroxyacetone led to asymmetric allylation though stereoselectivity was around 50% ee. Thus, the hidden aspect of the chemoselective nature of protected hydroxyacetone-derived enolate generated under thermodynamically controlled conditions has opened a new avenue for two-directional elaboration of hydroxyacetone that should be potentially useful in organic synthesis.