- Kinetic resolution of d,l-1,2-diols catalyzed by amine-phosphinite bifunctional organocatalysis derived from quinidine
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Racemic C2-symmetric 1,2-diols were kinetically resolved by the acylation reaction catalyzed by the phosphinite derivative of quinidine to afford the corresponding monoacylated product with good to high enantioselectivities.
- Mizuta, Shinya,Ohtsubo, Yutaka,Tsuzuki, Takeo,Fujimoto, Tetsuya,Yamamoto, Iwao
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p. 8227 - 8229
(2007/10/03)
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- In vitro metabolism of chloroprene: Species differences, epoxide stereochemistry and a de-chlorination pathway
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Chloroprene (1) was metabolized by liver microsomes from Sprague-Dawley rats, Fischer 344 rats, B6C3F1 mice, and humans to the monoepoxides, (1-chloro-ethenyl)oxirane (5a/5b), and 2-chloro-2-ethenyloxirane (4a/4b). The formation of 4a/4b was inferred from the identification of their degradation products. With male Sprague-Dawley and Fischer 344 rat liver microsomes, there was a ca. 3:2 preference for the formation of (R)-(1-chloroethenyl)oxirane (5a) compared to the (S)-enantiomer (5b). A smaller but distinct enantioselectivity in the formation of (S)-(1-chloro-ethenyl)oxirane occurred with liver microsomes from male mouse (R:S, 0.90:1) or male human (R:S, 0.86:1). 2-Chloro-2-ethenyloxirane was very unstable in the presence of the microsomal mixture and was rapidly converted to 1-hydroxybut-3-en-2-one (11) and 1-chlorobut-3-en-2-one (12). An additional rearrangement pathway of 2-chloro-2-ethenyloxirane gave rise to 2-chlorobut-3-en-1-al (14) and 2-chlorobut-2-en-1-al (15). Further reductive metabolism of these metabolites occurred to form 1-hydroxybutan-2-one (17) and 1-chlorobutan-2-one (18). In the absence of an epoxide hydrolase inhibitor, the microsomal incubations converted (1-chloroethenyl)oxirane to 3-chlorobut-3-ene-1,2-diol (21a/21b). When microsomal incubations were supplemented with glutathione, 1-hydroxybut-3-en-2-one was not detected because of its rapid conjugation with this thiol scavenger.
- Cottrell,Golding,Munter,Watson
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p. 1552 - 1562
(2007/10/03)
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