Direct N1-monosubstitution of piperazine
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| Year of publication | 2014 |
| MU Faculty or unit | |
| Citation | |
| Description | We report new methods for the efficient direct N1-monosubstitution of piperazine based on the reaction of piperazine-1-ium cation with different electrophilic agents optionally under catalysis by various metal ions supported on weakly acidic cation-exchanger resin. Starting piperazine-1-ium was generated in situ from piperazine in acetic acid solution or by chemi-sorption of piperazine on weakly acidic cation-exchanger resin (i. e. solid phase synthesis with ionically bonded substrate). These two methods were used for reaction with electrophilic reagents such as acyl chlorides, anhydrides, sulfonyl chlorides, carbamoyl chlorides, for example. For aza-Michael additions of piperazine-1-ium cation to compounds with an activated multiple carbon-carbon bond (derivatives of acrylic, propiolic and acetylenedicarboxylic acid) this cation was generated in methanol solution by mixing of piperazine with piperazine-1,4-diium dichloride in various proportions. It was found that solid support metal catalysis afforded target products in very good yields under shortening of reaction times. |
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