- Synthesis of [13C3]-B6 vitamers labelled at three consecutive positions starting from [13C3]-propionic acid
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[13C3]-labelled vitamers (PN, PL and PM) of the B6 group were prepared starting from [13C3]-propionic acid. [13C3]-PN was synthesized in ten linear steps with an overall yield of 17%. Hereby, higher alkyl homologues of involved esters showed a positive impact on the reaction outcome of the intermediates in the chosen synthetic route. Oxidation of [13C3]-PN to [13C3]-PL was undertaken using potassium permanganate and methylamine followed by acid hydrolysis of the imine derivative. [13C3]-PM could be prepared from the oxime derivative of [13C3]-PN by hydrogenation with palladium.
- Bachmann, Thomas,Rychlik, Michael
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- Nickel-catalyzed direct alkylation of heterocycles with α-bromo carbonyl compounds: C3-selective functionalization of 2-pyridones
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Nickel HAS it: A Ni(cod)2/dppp catalyst system promotes the direct alkylation of electron-rich heterocycles with α-bromo carbonyl compounds and involves an alkyl radical intermediate (see scheme; cod=1,5-cyclooctadiene, dppp=1,3-bis(diphenylphosphino)propane). This homolytic radical aromatic substitution (HAS)-type reaction enables the C3-selective direct functionalization of 2-pyridones. Copyright
- Nakatani, Akihiro,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information
p. 7691 - 7695
(2013/07/05)
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- Synthesis of some alkyl acetates from alcohols catalyzed by H 5PW10V2O40and H5PMo 10V2O40 under microwave irradiation(Part 2)
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The protection of alcohols under the environmentally benign microwave approach by the mediation of H5PMo10V2O40 and H5PW10V2O40 as vanadium-containing mixed-addenda heteropolyoxometalates with Keggin primary structure was investigated. The influence of microwave power on the progress of 1-butanol acetylation with acetic acid in the presence of a catalytic amount of H5PW10V2O40 has also been studied. To study the recycle ability and stability of the catalyst, H5PW10V2O40 was regenerated at the end of the protection reaction. The catalyst was washed with dichloromethane, dried at room temperature and finally was heated to 130°C for 3h. Catalytic amounts of cheap and simple Keggin type H5PM10V2 led to protection of alcohols with acetic acid in high yields, with reduced reaction times under solvent free conditions.
- Tayebee, Reza,Zonoz, Farokhzad Mohammadi
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experimental part
p. 541 - 545
(2011/09/16)
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- Esterification of carboxylic acid salts
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Mono- or polycarboxylic acid esters are prepared by reacting a salt of such carboxylic acid with an organic halocompound, e.g., a (cyclo)alkyl, (cyclo)alkenyl, aryl or aralkyl halide, in an aqueous reaction medium, in the presence of a catalytically effective amount of a phase transfer catalyst, for example an onium salt.
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