n-Propyl-2,2,3,3,3-d5-amine Hydrochloride is the hydrochloride salt of 1-Propyl-d5-amine (P833702); the isotope labelled analog of 1-Propylamine (P833700) which is used in the synthesis of pyrimidine derivatives as novel and highly potent PDE4 inhibitors. It is also used in the preparation of fluorenone analogs with DNA topisomerase I inhibitors.