1,4-Cyclohexanedione Monoethylene Acetal-d4 is the labeled analogue of 1,4-Cyclohexanedione Monoethylene Acetal (C987955), which is used in the preparation of series of potent analgesic compounds. 1,4-Cyclohexanedione Monoethylene Acetal is also used as a building block in the synthesis of tritium labelled probes for the autoradiography study of the dopamine reuptake complex.