- Synthesis of 2,2-Dichloro-1-alkanols
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2,2-Dichloro-1-alkanols were prepared conveniently by sodium borohydride reduction of 2,2-dichloroaldehydes.
- Salgado, Antonio,Huybrechts, Tom,De Buyck, Laurent,Czombos, Jozsef,Tkachev, Alexey,De Kimpe, Norbert
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- 2,2-dichloroaldehydes and 2,2-dichlorocarboxylic acids from 2- picoline·HCl catalyzed chlorination of aldehydes
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An efficient preparation of 2,2-dichloroaldehydes and 2,2- dichlorocarboxylic acids has been achieved by chlorination of aldehydes using 2-picoline hydrochloride as recoverable catalyst.
- Bellesia, Franco,De Buyck, Laurent,Ghelfi, Franco
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p. 146 - 148
(2007/10/03)
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- α,α-DICHLOROALDEHYDES AND α,α-DICHLOROCARBOXYLIC ACIDS FROM LONG CHAIN 1-ALKANOLS. IMPROVED CHLORINATION IN THE SYSTEM DMF-CHCl3-MgCl2
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Production of α,α-dichloroaldehydes by direct chlorination of 1-alkanols with chlorine gas, catalyzed by DMF and DMF*HCl, was extended to long chain compounds (CnH2n+1OH; n = 5, 6, 8, 10, 12, 14, 16, 18).Two problems specific to the longer chains were solved to obtain isolated yields in the range 70-85 percent; a) parasitic radical chlorination was largely controlled by shielding from light; b) alkyl alkanoate side product (8 percent for n = 8 but 25 percent for n = 16 or 18) was decreased to 0-2 percent in the presence of MgCl2*H2O.Homogeneity of the reaction medium was improved with chloroform as a cosolvent.Oxidation of the aldehydes to dichlorocarboxylic acids proceeded smoothly with aqueous KMnO4 up to the tetradecanal.For the longer chains 30 percent hydrogen peroxide-NaHCO3 in acetone (overnight at 48-52 deg C) was the preferred oxidant.
- Buyck, L. De,Casaert, F.,Lepeleire, C. De,Schamp, N.
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p. 525 - 534
(2007/10/02)
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- CONVENIENT APPROACHES TO HETEROCYCLES VIA COPPER-CATALYSED ADDITIONS OF ORGANIC POLYHALIDES TO ACTIVATED OLEFINS
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An efficient method for the synthesis of 2,3-dichloro-5-substituted (Cl, CF3, alkyl) pyridines 29 starting from the 1:1 adducts of the copper-catalysed addition of chloral or the corresponding 2,2-dichloroaldehydes to acrylonitrile is presented.Proper choice of experimental conditions allows the preparation of 29 in one-pot process.Similarly, the CuCl-catalysed reaction of methyl itaconate with several trichloromethyl compounds R-CCl3 gives 6-R-substituted 2-pyrone derivatives 40 via dehalogenation and subsequent thermal ring closure of the primary 1:1-adducts. The new electrophilic 2-pyrone 40b undergoes-cycloaddition reactions with inverse electron demand with a number of olefins and acetylenes, allowing thereby regioselective transfer of a trifluoromethyl group from a simple Freon derivative (1,1,1-trichloro-2,2,2-trifluoroethane) into more complex organic molecules.Finally, the 1:1-adduct of trichloroacetylchloride with methyl acrylate allows a very covenient synthesis of novel N-substituted derivatives 66 of pyroglutamic acid as well as of proline.
- Martin, Pierre,Steiner, Eginhard,Streith, Jacques,Winkler, Tammo,Bellus, Daniel
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p. 4057 - 4078
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF (S)-METHYL-3-HYDROXYALKANOATES FROM KETENE AND 2,2-DICHLOROALDEHYDES VIA 4-(1,1-DICHLOROALKYL)-2-OXETANONES
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Using the quinidine catalyzed cycloaddition reaction of ketene and 2,2-dichloroaldehydes, the preparation of several optically pure (S)-methyl-3-hydroxyalkanoates is reported.
- Ketelaar, Peter E.F.,Staring, Emiel G.J.,Wynberg, Hans
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p. 4665 - 4668
(2007/10/02)
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- 2,2-DICHLOROALDEHYDES FROM ALDEHYDES AND ALCOHOLS BY CHLORINATION IN DIMETHYLFORMAMIDE
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A method is described for the synthesis of α,α-dichloroaldehydes, free from monochloroaldehyde, by chlorination of aldehydes or alcohols in dimethylformamide at 40-90 deg C.Results are reported for : (yield percent) propanal (90), butanal (78), pentanal (78), 3-methylbutanal (90), propanol (64), butanol (78), 3-methylbutanol (52), pentanol (66), 3,3-dimethylbutanol (86), hexanol (66), 2-phenylethanol (51), 3-phenylpropanol (54), 1,5-pentanediol , 1,6-hexanediol .Oxidative conversion (KMnO4, K2Cr2O7, H2O2-NaHCO3) into α,α-dichlorocarboxylic acids and methyl esters is discussed.
- Buyck, L. De,Verhe, R.,Kimpe, N. De,Courtheyn, D.,Schamp, N.
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p. 441 - 458
(2007/10/02)
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