Aminomethylation of substituted pyrroles and 4,5,6,7-tetrahydroindoles with biogenic cyclic amines

Abstract

Aminomethylation of 2-methyl(aryl)-, 2-aryl-3-alkylpyrroles, 4,5,6,7-tetrahydroindole and its 1-vinyl- and 1-benzyl-substituted derivatives with a mixture of 5% water-ethanol solution of formaldehyde and cyclic amine (pyrrolidine, piperazine, and morpholine) without catalyst at room temperature leads to the formation of the corresponding 2-aminomethylpyrroles and 2-aminomethyl-4,5,6,7-tetrahydroindoles in up to 92% yields. In reaction of 1-vinyl-4,5,6,7-tetrahydroindole with formaldehyde water solution and piperazine in a 60% yield 1,4-bis(1-vinyl-4,5,6,7-tetrahydroindol-2-yl)piperazine was obtained, a promising bifunctional monomer and a building block for the synthesis of new indole derivatives, in particular, of biologically active polymers. In the reaction of 2-methylpyrrole and 4,5,6,7-tetrahydroindole with formaldehyde and morpholine along with the С²-aminomethylation the 1-hydroxymethylation of the pyrrole ring was observed.