108530-03-6Relevant academic research and scientific papers
Synthesis of Enantiomerically Enriched Drug Precursors by Lactobacillus paracasei BD87E6 as a Biocatalyst
?ksüz, Selda,?ahin, Engin,Dertli, Enes
, (2018)
Global sales of single enantiomeric drug products are growing at an alarming rate every year. A total of 7 bacterial strains were screened for their ability to reduce acetophenones to its corresponding alcohol. Among these strains Lactobacillus paracasei BD87E6 was found to be the most successful biocatalyst to reduce the ketones to the corresponding alcohols. The reaction conditions were systematically optimized for the reducing agent Lactobacillus paracasei BD87E6, which showed high enantioselectivity and conversion for the bioreduction. The preparative scale asymmetric reduction of 3-methoxyacetophenone (1h) by Lactobacillus paracasei BD87E6 gave (R)-1-(3-methoxyphenyl)ethanol (2h) with 92% yield and 99% enantiomeric excess. Compound 2h could be used for the synthesis of (S)-rivastigmine which has a great potential for the treatment of Alzheimer's disease. This study demonstrates that Lactobacillus paracasei BD87E6 can be used as a biocatalyst to obtain chiral carbinol with excellent yield and selectivity. The whole cell catalyzed the reductions of ketone substrates on the preparative scale, demonstrating that Lactobacillus paracasei BD87E6 would be a valuable biocatalyst for the preparation of chiral aromatic alcohols of pharmaceutical interest.
Efficient and recyclable Ru(II) arene thioamide catalysts for transfer hydrogenation of ketones: Influence of substituent on catalytic outcome
Kanchanadevi, Appukutti,Ramesh, Rengan,Semeril, David
, p. 68 - 77 (2016)
Six cationic ruthenium(II) arene thioamide complexes with the general molecular formula [Ru(η6-p-cymene)(PPh3)(L)]+ [where, L = pyridine-2-thioamide and its derivatives] have been successfully synthesized from the reaction of [Ru(η6-p-cymene)Cl2]2 with chelating thioamide ligands and PPh3 in methanol in 1:2 M ratio respectively. All the complexes were isolated as their BPh4?salts and were fully characterized by analytical and spectral (FT-IR, UV-Vis and1H-NMR) methods. The solid-state structure of one of the complexes, [Ru(η6-p-cymene)(PPh3)(L4)]BPh4 (4) (L4 = N-(2, 4, 6-Trimethylphenyl)pyridine-2-thiocarboxamide) has been established by X-ray single crystal diffraction which indicates a pseudo-octahedral (piano-stool) coordination geometry is present in the complex. The ruthenium(II) complexes have been examined for the transfer hydrogenation of various aromatic, heterocycle and cyclic ketones. The formation of ruthenium(II) hydride is confirmed by 1H- NMR and is proposed as the catalytic intermediate in this reaction. Under the optimized conditions, these ruthenium complexes served as excellent catalyst precursors which smoothly reduce the ketones with conversion up to 100%. The influence of other variables on the transfer hydrogenation reaction such as solvent, base, temperature, time, catalyst loading and substrate scope is also reported. Furthermore, the catalyst could be easily recovered and reused at least three times without obvious loss of conversions.
Synthesis of light-induced expandable photoresponsive polymeric nanoparticles for triggered release
Wang, Zhen,Wang, Peng,Tang, Xinjing
, p. 1273 - 1281 (2013)
High stability of drug-delivery nanocarriers during blood circulation is critical for effective drug delivery and low systematic toxicity, although destabilization of these nanocarriers is required for efficient release when they reach target sites. To develop efficient polymeric nanocarriers, we intended to synthesize and characterize a group of cross-linked, light-induced, expandable, polymeric nanoparticles through miniemulsion polymerization. These synthesized nanoparticles were stable in aqueous solutions, although light irradiation led to particle uncaging and further particle expansion up to 315-fold in volume. This resulted in the efficient release of the encapsulated contents in aqueous solutions and three cell lines (HeLa, RAW264.7, and MCF-7). Selective triggered release was also successfully achieved with spatial resolution in cell monolayers. In addition, curcumin encapsulation and photoregulation of its release were realized. Further cell viability of encapsulated curcumin was successfully achieved with light activation. Open the cage: A series of cross-linked photolabile polymeric nanoparticles are described. Light irradiation leads to the particle swelling 315-fold in volume and the efficient release of the encapsulated contents in both aqueous solutions and cells. Selective triggered release on a cell monolayer is achieved. Curcumin is efficiently encapsulated in particles and photoregulation of its release and cell viability is also successfully achieved. Copyright
Synthesis of [15N] and [side-chain 1-13C] isotopomers of 1-(2-nitrophenyl)ethyl phosphates
Corrie
, p. 403 - 410 (1996)
Nitration of 1-phenylethyl acetate with NH4NO3-trifluoroacetic anhydride gave a mixture of ortho- and para-nitro products, which were separable by chromatography after saponification of the acetate. The ortho-isomer [1-(2-nitrophenyl)ethanol] was converted to the 1-(2-nitrophenyl)ethyl esters of monomethyl phosphate and of the γ-phosphate of ATP. The title isotopomers were prepared using either ammonium [15N]nitrate or [side-chain 1-13C]1-phenylethyl acetate as starting materials. A correction is made to the reported 1H NMR spectrum of caged ATP and the effects of isotopic substitution on the mass spectral fragmentation of 1-(2-nitrophenyl)ethanol are tabulated.
Release of Terminal Alkynes via Tandem Photodeprotection and Decarboxylation of o -Nitrobenzyl Arylpropiolates in a Flow Microchannel Reactor
Tebikachew, Behabitu Ergette,B?rjesson, Karl,Kann, Nina,Moth-Poulsen, Kasper
, p. 1178 - 1185 (2018)
Photocleavable protecting groups (PPGs) offer a complementary protection paradigm compared to traditional protection groups. Herein, an o-nitrobenzyl (NB) PPG was employed to protect a variety of arylpropiolic acids. Upon a cascade of light-triggered photodeprotection in a microchannel reactor (residence times of 100-500 s), followed by Cu-catalyzed decarboxylation at 60 °C, the NB-protected arylpropiolic acid afforded a terminal alkyne. This terminal alkyne was further reacted in situ with an azide via click chemistry to yield a 1,2,3-triazole in a one-pot reaction. Furthermore, the effect of different substituents (methyl, vinyl, allyl, and phenyl) at the benzylic position on the rate of photodeprotection was studied. The quantum yields of photolysis for the benzylic-substituted esters were determined to be as high as 0.45 compared to the unsubstituted ester with a 0.08 quantum yield of photolysis.
Methyl-triisopropoxy-titanium, a Highly Selective Nucleophilic Methylating Reagent
Weidmann, Beat,Seebach, Dieter
, p. 2451 - 2454 (1980)
Replacement of lithium or magnesium by titanium can furnish nucleophilic organometallic reagents of high selectivity as exemplified by the title compound 1 (see Tables 1-3).
Enantioselective Addition of Chiral Organotitanium Derivatives to Aldehydes
Olivero, Alan G.,Weidmann, Beat,Seebach, Dieter
, p. 2485 - 2488 (1981)
Alkoxy- and aryloxy-organotitanum compounds 2-4 derived from (S)-2-methyl-1-butanol, (R)-2-butanol, (-)-menthol, quinine, cinchonine, and (S)-1,1'-binaphthol are added to aromiatic aldehydes to give optically active alcohols 5-10 in enantioselectivities of up to 88percent e.e., with nucleophilic transfer of methyl, phenyl, and 1-naphthyl groups.The Tables 1-3 list the effects of varying the reagents, the substrates, and the reaction conditions of the new asymmetric synthesis.
Asymmetric transfer hydrogenation of aromatic ketones catalyzed by the iridium hydride complex under ambient conditions
Chen, Jian-Shan,Li, Yan-Yun,Dong, Zhen-Rong,Li, Bao-Zhu,Gao, Jing-Xing
, p. 8415 - 8418 (2004)
The chiral Ir catalytic system generated in situ from iridium hydride complex and chiral diaminodiphosphine ligand was employed in asymmetric transfer hydrogenation of aromatic ketones to give the corresponding optically active alcohols, with up to 99% ee
Chemoselective Derivatization of Folded Synthetic Insulin Variants with Potassium Acyltrifluoroborates (KATs)
Boross, Gábor N.,Schauenburg, Dominik,Bode, Jeffrey W.
, (2019)
Synthetic folded insulin variants containing an ornithine-hydroxylamine residue are readily modified in aqueous buffers by amide-forming ligations with potassium acyltrifluoroborates (KATs). The synthetic insulin analogs were prepared by Fmoc-SPPS, α-keto
Debaryomyces hansenii as a new biocatalyst in the asymmetric reduction of substituted acetophenones
?ahin, Engin
, p. 363 - 371 (2017)
Chiral secondary alcohols are convenient mediator for the synthesis of biologically active compounds and natural products. In this study fifteen yeast strains belonging to three food originated yeast species Debaryomyces hansenii, Saccharomyces cerevisiae and Hanseniaspora guilliermondii were tested for their capability for the asymmetric reduction of acetophenone to 1-phenylethanol as biocatalyst microorganisms. Of these strains, Debaryomyces hansenii P1 strain showed an effective asymmetric reduction ability. Under optimized conditions, substituted acetophenones were converted to the corresponding optically active secondary alcohols in up to 99% enantiomeric excess and at high conversion rates. This is the first report on the enantioselective reduction of acetophenone by D. hansenii P1 from past?rma, a fermented Turkish meat product. The preparative scale asymmetric bio reduction of 3-methoxy acetophenone 1g by D. hansenii P1 gave (R)-1-(3-methoxyphenyl) ethanol 2g 82% yield, and >99% enantiomeric excess. Compound 2g can be used for the synthesis of (+)-NPS-R-568 [3-(2-chlorophenyl)-N-[(1R)-1-(3-methoxyphenly) ethyl] propan-1-amine] which have a great potential for the treatment of primary and secondary hyper-parathyroidism. In addition, D. hansenii P1 successfully reduced acetophenone derivatives. This study showed that this yeast can be used industrially to produce enantiomerically pure chiral secondary alcohols, which can be easily converted to different functional groups.
