N-Methyl-NтАЩ-nitrosopiperazine-d4 is the isotope labelled analog of N-Methyl-NтАЩ-nitrosopiperazine (M325800), which is used as a reagent in the organic synthesis of several compounds including that of (4-methoxyphenoxy)acetic and (3,4,5-trimethoxyphenoxy)acetic acid amides and hydrazides which display antimicrobial and anthelmintic properties and may act as potential neurotropic and cardiovascular agents. N-Methyl-NтАЩ-nitrosopiperazine also diplayed strong nasal carcinogenity and genotoxicity toward nasal cells.