- A PROCESS FOR THE PREPARATION OF SOFOSBUVIR INTERMEDIATES and ITS POLYMORPH
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The present invention provides a novel process for preparation N-[(2,3,4,5,6- Pentafluorophenoxy)phenoxyphosphinyl]-L-alanine 1-methylethyl ester (formula 2) and resolving the formula 2 in the presence base to form N-[(S)-(2,3,4,5,6- Pentafluorophenoxy)phenoxyphosphinyl]-L-alanine 1-methylethyl ester (formula 2').
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Page/Page column 6
(2016/12/01)
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- Enantioselective nucleophile-catalyzed synthesis of tertiary alkyl fluorides via the α-Fluorination of ketenes: Synthetic and mechanistic studies
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The catalytic asymmetric synthesis of alkyl fluorides, particularly α-fluorocarbonyl compounds, has been the focus of substantial effort in recent years. While significant progress has been described in the formation of enantioenriched secondary alkyl flu
- Lee, Sarah Yunmi,Neufeind, Stefan,Fu, Gregory C.
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supporting information
p. 8899 - 8902
(2014/07/08)
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- A mechanistic study of the alkaline hydrolysis of diaryl sulfate diesters
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Nearly all of the reported studies of reactions of sulfate diesters are for dialkyl or alkyl aryl diesters, which undergo reaction by carbon-oxygen bond fission. Sulfuryl transfer reactions of sulfate diesters (RO-SO 2-OR′) proceeding by attack at sulfur have been little explored. When both ester groups are aryl groups the hydrolysis reaction (sulfuryl transfer to water) occurs by way of attack at sulfur. The alkaline hydrolysis of diaryl sulfate diesters was shown to obey first-order kinetics with respect to [-OH] and proceed through S-O bond fission, in a mechanism that is most likely concerted. Activation parameters for 4-chloro-3-nitrophenyl phenyl sulfate and 4-nitrophenyl phenyl sulfate gave the following respective values: ΔH? = 88.0 ± 0.1 and 84.83 ± 0.06 kJ mol-1 and ΔS? = -37 ± 1 and -50.2 ± 0.5 J mol-1 deg-1. The dependence of the second-order rate constant for hydrolysis on leaving group pKa was analyzed giving a β1g slope of -0.7 ± 0.2 and a Leffler α parameter value of 0.36. A 15k kinetic isotope effect (KIE) for the hydroxide attack on 4-nitrophenyl phenyl sulfate of 1.0000 ±0.0005 and an 18k1g KIE value of 1.003±0.002 were obtained.
- Younker, Jarod M.,Hengge, Alvan C.
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p. 9043 - 9048
(2007/10/03)
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- New access to cross-coupling reaction between arylsilanes or heteroarylsilanes and aryl halides mediated by a copper(I) salt
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Copper(I) salt can be used as a promoter for the cross-coupling reactions between aryl- or heteroarylsilanes and aryl halides without a fluoride ion. Under these mild conditions, even a substrate containing a fluoride ion-sensitive silyloxyl group was employed directly.
- Ito, Hajime,Sensui, Hiro-Omi,Arimoto, Kikuo,Miura, Katsukiyo,Hosomi, Akira
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p. 639 - 640
(2007/10/03)
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- Electron Affinities of Fluorinated Phenoxy Radicals
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The electron-capture coefficients for five fluorophenoxy phenyl ethers have been determined by using "short" pulse intervals.The temperature dependence of the electron-capture coeficients can be used to determine the electron affinities of the molecules a
- Hernandez-Gil, N.,Wentworth, W. E.,Chen, E. C. M.
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p. 6181 - 6185
(2007/10/02)
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