- Synthesis of enantiomerically enriched-bromonitriles from amino acids
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Two methods were investigated for the preparation of six chiral-bromonitriles with different optic purities. The nitrous deamination of amino acids gives-bromoacids, which react with chlorosulfonyl isocyanate followed by triethylamine to afford-bromonitriles with moderate enantiomeric excess. However, the dehydration of corresponding-bromoamids using thionyl chloride gives-bromonitriles with good enantiomeric excess up to 94%. The use of phosphoryl chloride instead of thionyl chloride results in more than 30% racemization as determined by high-performance liquid chromatograpic analysis.
- Tka, Najeh,Kraem, Jamil,Hassine, Bechir Ben
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p. 735 - 743
(2013/01/15)
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- Oxidative Decyanation of Secondary Nitriles to Ketones
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Procedures for the oxidative decyanation of secondary nitriles to ketones involve (1) iodination of N-(trialkylsilyl)ketenimines derived from secondary nitriles and subsequent hydrolysis of the α-iodo nitriles with silver oxide, (2) addition of nitrosobenzene to N-(trialkylsilyl)ketenimines, (3) conversion of secondary nitriles to α-(phenylthio) nitriles and subsequent hydrolysis with N-bromosuccinimide in aqueous acetonitrile, and (4) preparation of α-hydroperoxy nitriles by direct oxygenation of anions of secondary nitriles and subsequent reductive hydrolysis with stannous chloride followed by sodium hydroxide.The latter general procedure was applied to various secondary nitriles bearing dialkyl, aryl and alkyl, and diaryl substituents to provide ketones in good yield and was extended to the oxidative decyanation of α,β-unsaturated nitriles to furnish α,β-unsaturated ketones.
- Freerksen, Robert W.,Selikson, Sandra J.,Wroble, Randall R.,Kyler, S. Keith,Watt, David S.
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p. 4087 - 4096
(2007/10/02)
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