Synthesis of substituted chloroacetylenes from methyl ketones

1. Depending on the conditions, the reaction of methyl aryl ketones with phosphorus pentachloride leads to products from substitution of the carbonyl oxygen by chlorine, αβ-dichlorovinylarenes, or compounds with higher degrees of chlorination. 2. By eliminating a molecule of hydrogen chloride under the influence of an equimolar amount of sodium amide in ammonia, substituted, α,β-dichloroethylenes give high yields of the respective 2-chloroacetylene. 3. The synthesis of a series of ethynyl- and β-chloroethynylpyrazoles from methylpyrazolyl ketones was realized.