N-Haloalkylation Reaction in the Presence of Trichloroacetic Acid

Abstract

N-Substituted ureas, thioureas, and related compounds find applications in industry, engineering, agriculture, and medicine, therefore the interest of researchers is still attracted by the synthesis of these substances. We formerly investigated the nucleophilic substitution of a hydroxy group in alkoxyand alkylthio-substituted 1,2-chlorohydrins by weak N-nucleophiles, like urea and thiourea, in the presence of trifluoroacetic acid [1, 2] and in a mixture of sulfuric and acetic acids [3]. From these reactions resulted various alkoxyand alkylthio-substituted carbamides and thiocarbamides. The practical value of N-alkylation reactions used nowadays is limited by the requirement to perform them in the concentrated mineral acids. The processes of this type in the presence of trichloroacetic acid were not described in the literature. It turned out that the piperidine, a stronger base than urea, reacted with ethylene chlorohydrin in the presence of trichloroacetic acid affording in a 65% yield N-(2chloroethyl)piperidine (I).