125224-44-4Relevant academic research and scientific papers
Isomerization-Asymmetric Hydrogenation Sequence Converting Racemic β-Ylidenecycloalkanols into Stereocontrolled β-Substituted Cycloalkanols Using a Ru Catalytic System with Dual Roles
Arai, Noriyoshi,Okabe, Yuki,Ohkuma, Takeshi
, p. 5540 - 5547 (2019/11/16)
Racemic β-ylidenecycloalkanols were transformed into the cis-β-substituted cycloalkanols with high enantio- and diastereoselectivities through an isomerization-asymmetric hydrogenation sequence with the (4,4′-bi-1,3-benzodioxole)-5,5′-diylbis[di(3,5-xylyl)phosphine (DM-Segphos)/2-dimethylamino-1-phenylethylamine (DMAPEN)-ruthenium(II) catalyst; such transformation hardly proceeded by single-step asymmetric hydrogenation. The reaction was usually carried out with a substrate-to-catalyst molar ratio of 500 under 4 to 10 atm of H2 to afford the products in cis/trans ratio up to 99:1 and 98% ee. Mechanistic experiments suggested that this catalytic system reversibly formed two reactive species, types (I) and (II), through a ruthenacyclic amide intermediate. The amide complex and allylic alcohol reacted to afford the allylic alkoxide complex with partial or full removal of diamine (type (I)), and this type (I) complex catalyzed isomerization of the allylic alcohols into the racemic α-substituted ketones. The RuH2 complex with chelation of diamine (type (II)) formed by reaction of the amide complex and hydrogen promoted asymmetric hydrogenation of racemic α-substituted ketone into the stereocontrolled β-substituted cycloalkanols through dynamic kinetic resolution. (Figure presented.).
Lipase activity enhancement by SC-CO2 treatment
Hlavsova, Klara,Wimmer, Zdenek,Xanthakis, Epameinondas,Bernasek, Prokop,Sovova, Helena,Zarevucka, Marie
experimental part, p. 779 - 784 (2009/02/06)
The activity of lipases from porcine pancreas, Candida antartica recombinant from Aspergillus oryzae, Candida cylindracea (immobilized), Penicilium roqueforti, Aspergillus niger, Rhizopus arrhizus, Mucor miehei (two types of immobilization), and Pseudomonas cepacia (two types of immobilization) was studied after using them as biocatalysts of blackcurrant oil hydrolysis under SC-CO2 conditions. The reaction was performed at 40°C and 15 MPa in a continuous-flow reactor. Increased relative activity of all used lipases after the hydrolytic reaction was observed. The most remarkable increase in the activity was noted for the lipase from Rhizopus arrhizus which was increased by more than 50 times. The highest activity was shown by Lipozyme, lipase from Mucor miehei, immobilized on macroporous resin. Both treated and untreated Lipozyme were used as biocatalysts in hydrolytic resolution of the racemic cis- or frani-isomers of 2-(4-methoxybenzyl) cyclIohexyl acetates. Satisfactory reaction yields (40 %) and excellent enantiomeric purity of the products (E = 472) were obtained when hydrolysis of the frans-isomer of 2-(4-methoxybenzyl)cyclohexyl acetate was catalyzed by Lipozyme treated with SC-CO2.
Insect pest control agents: Novel chiral butanoate esters (juvenogens)
Wimmer, Zdenek,Floro, Alexandra J.F.D.M.,Zarevucka, Marie,Wimmerova, Martina,Sello, Guido,Orsini, Fulvia
, p. 6037 - 6042 (2008/03/28)
During the investigation of ester derivatives (juvenogens, biochemically activated insect hormonogenic compounds) of biologically active alcohols with potential application in insect pest control, a need for availability of all existing stereoisomers of e
Application of ionic liquids in enzymic resolution by hydrolysis of cycloalkyl acetates
Xanthakis, Epameinondas,Zarevucka, Marie,Saman, David,Wimmerova, Martina,Kolisis, Fragiskos N.,Wimmer, Zdenek
, p. 2987 - 2992 (2007/10/03)
A comparative study was performed in the enzymic resolution of the isomers of 2-(4-methoxybenzyl)cyclohexyl acetates 1 and 2. The investigation consisted in application of three commercially available lipases (Novozyme 435, Lipozyme IM and non-immobilized
Enzymic resolution of 2-substituted cyclohexanols through lipase-mediated esterification
Wimmer, Zdenek,Skouridou, Vasso,Zarevucka, Marie,Saman, David,Kolisis, Fragiskos N.
, p. 3911 - 3917 (2007/10/03)
Several lipases were used for the kinetic resolution of the racemic cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexanol, by lipase-mediated esterification of the substrates to the corresponding acetate isomers. Lipase from Rhizomucor miehei was foun
Synthesis and structure-activity relationships of juvenoids derived from 2-(4-hydroxybenzyl)cycloalkan-1-ones
Rejzek,Wimmer,Saman,Ricankova,Nemec
, p. 1241 - 1255 (2007/10/02)
Juvenoids 16-30, 32, 36, 38-41, 44-46, and 49-56 containing carbamate, carbonate, and urea moieties in the molecule were synthesized and subjected to a biological screening. Carbamate juvenoids 1-4 were used as reference compounds for a detailed structure-activity study of their analogues. A clear relationship between the nature of the side chain functional group and the biological activity was found. Surprisingly, not only the juvenoids 1,4 but also 38-41, the compounds with a reversed carbamate N,O-substitution pattern, showed very promising biological activity. In contrast, the carbonate and urea derivatives displayed a remarkably low activity. The relationship between the size and substitution at atoms C(2) and C(3) of the saturated ring and the biological activity is very complex and is still not completely understood.
CONFORMATION STUDIES OF ISOMERIC 1-ACYLOXY-2-(4-METHOXYBENZYL)-CYCLOHEXANES BY 1H NMR SPECTTOSCOPY
Budesinsky, Milos,Saman, David,Wimmer, Zdenek
, p. 2763 - 2767 (2007/10/02)
The conformation of the cyclohexane ring and the p-methoxybenzyl substituent in the series of isomeric 1-acyloxy-2-(4-methoxybenzyl)cyclohexanes was studied by means of 1H NMR spectroscopy.In all the substances investigated the cyclohexane ring assumes ch
