Methylpropylcarbamic Acid 1,1-Dimethylethyl Ester-D3 is an intermediate used in the synthesis of 2-Oxo-3-hydroxy-N-methyl-N-propyl D-Lysergamide-d3 (O856883), which is a labeled analogue of 2-Oxo-3-hydroxy-N-methyl-N-propyl D-Lysergamide (O856880), major metabolite of Lysergamide (L487990) used as internal standard.