The synthesis of Nπ-alkylhistamines

Abstract

The use of the phthaloyl and pivaloyloxymethyl protecting groups in a new synthesis of N^π-alkylhistamines is described. The N^α-phthaloyl-N^τ-pivaloyloxymethyl-protected derivative of histamine was obtained by selective alkylation of N^α-phthaloylhistamine with chloromethyl pivalate. Quaternisation at the N^π-nitrogen atom with either mtethyl iodide or benzyl bromide followed by removal of the protecting groups, either simultaneously or sequentially, furnished the required N^π methyl- and N^π-benzyl-histamines.