- PRACTICAL SYNTHESIS OF 2,2,5,5-TETRACHLORO-1,6-HEXANEDIOIC ACID, FROM TRANS-1,2-CYCLOHEXANEDIOL OR CYCLOHEXANONE, INVOLVING OXIDATION OF 3,3,6,6-TETRACHLORO-1,2-CYCLOHEXANEDIONE
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Trans-1,2-cyclohexanediol was quantitatively converted into 3,3,6,6-tetrachloro-1,2-cyclohexanedione (2) by treatment with chlorine in dimethylformamide.The hydrate of the dione was oxidized by aqueous potassium permanganate to afford the title acid 1 in 91percent overall yield.An alternative low cost preparation was elaborated, providing 2 in 61-74percent yield starting from cyclohexanone in a three step procedure without isolation of intermediates.The reaction seqence involves substitution of α-dichloro- and trichlorocyclohexanones by sodium acetate in acetic acid and chlorination of the resulting 2-hydroxy- and 2-acetoxy-2-cyclohexenones in dimethylformamide.
- Buyck, Laurent de,Vanslembrouck, Jan,Kimpe, Norbert de,Verhe, Roland,Schamp, Niceas
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p. 913 - 918
(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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