3616-83-9Relevant academic research and scientific papers
Chiral Pyridines: Optical Resolution of 1-(2-Pyridyl)- and 1-[6-(2,2′-Bipyridyl)]ethanols by Lipase-Catalyzed Enantioselective Acetylation
Uenishi, Jun'ichi,Hiraoka, Takao,Hata, Shinichiro,Nishiwaki, Kenji,Yonemitsu, Osamu,Nakamura, Kaoru,Tsukube, Hiroshi
, p. 2481 - 2487 (2007/10/03)
The resolution of racemic 1-(2-pyridyl)ethanols 2a-n, including the 2,2′-bipyridyl and isoquinolyl derivatives, by lipase-catalyzed asymmetric acetylation with vinyl acetate is reported. The reactions were carried out in diisopropyl ether at either room temperature or 60°C using Candida antarctica lipase (CAL) to give (R)-acetate and unreacted (S)-alcohol with excellent enantiomeric purities in good yields. The reaction rate was relatively slow at room temperature for substrates bearing an sp3-type carbon at the 6-position on the pyridine ring, such as 2c, 2d, and 2e, and for those bearing 1-hydroxypropyl and allyl groups at the 2-position on the pyridine ring, such as 21 and 2m. In such cases, a higher temperature was required. Thus, when the reaction was conducted at 60°C, it was accelerated 3- to 7-fold without losing the high enantiospecificity. However, the reaction of homoallylic alcohol 2n was not complete, even when the reaction was continued for a longer period of time at 60°C. This enzymatic resolution can be used practically in a wide range of reaction scales from 10 mg to 10 g or more. This catalyst can be used repeatedly with a 5-10% loss of the initial activity with each use.
Biotransformation of phenyl- and pyridylalkane derivatives in rat liver 9,000xg supernatant (S-9)
Takeshita, Mitsuhiro,Miura, Masatomo,Unuma, Yukiko,Iwai, Sakiko,Sato, Izumi,Hongo, Takahiko,Arai, Toshie,Kosaka, Kazuhiro
, p. 831 - 836 (2007/10/03)
When phenylpropanes were incubated with phenobarbital-pretreated rat liver 9,000xg supernatant (S-9), oxidative hydroxylation occurred to give phenylpropanol (racemic), (1R, 2S)- and (1R, 2R)-phenylpropanediols, (2S)-hydroxyphenylpropanone. Incubation of pyridylethane and propane with S-9 afforded α-pyridylethanol and propanol, but those were optically inactive. During the incubation of 1-phenylpropanone, an asymmetric redox reaction simultaneously occurred to give (2S)-phenylpropanol, (1R, 2S)- or (1R, 2R)-phenylpropanediols and (2R)-hydroxyphenylpropanone. Acetylpyridines were enantioselectively reduced to afford α-pyridylethanols in high optical yields (94-98%ee). The oxidation of pyridylalkane was significantly inhibited by cytochrome P-450 inhibitor (SKF-525A), but reduction of acetylpyridines was not inhibited. Thus, cytochrome P-450 was found to be responsible for the oxidation of pyridylalkane, but not for the reduction of the ketone.
Chiral Pyridyl Alcohol-Promoted Highly Enantioselective and Rapid Addition of Dialkylzinc to Pyridinecarboxaldehydes
Ishizaki, Miyuki,Hoshino, Osamu
, p. 1337 - 1340 (2007/10/02)
Optically active 1-(2-, 3-, and 4-pyridyl)propanols and 1-(3-pyridyl)ethanol were synthesized in good to high enantiomeric excesses (up to 88percent e.e.) and in a short reaction time by catalyzed asymmetric addition of dialkylzinc to pyridine-2-, 3- and 4-carboxaldehydes and 6-bromopyridine-2-carboxaldehyde in the presence of tridentate chiral 2--1,1-diarylethanols.
