| Popis: |
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°C. Results are reported for: (yield %) 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 [3,3-dichloro-2-hydroxytetrahydropyran (37), 2,3,3-trichlorotetrahydropyran (19)], 1,6-hexanediol [2,2,5,5-tetrachloro-1,6-hexanedial (63)]. Oxidative conversion (KMnO4, K2Cr2O7, H2O2-NaHCO3) into α,α-dichlorocarboxylic acids and methyl esters is discussed. |
