Conversion of erythro-D-sphinganine to its [1-2H1] and [1-3H1] derivatives

A convenient chemical synthesis of erythro-D-[1-2H1] sphinganine and erythro-D-[1-3H1]sphinganine is described. The approach utilizes a stereospecific starting material (natural sphinganine prepared from bovine brain sphingomyelin) and applies a sequence of selective protection of functional groups yielding 2-acetamido-3-O-benzoyloctadecan-1-ol. Oxidation of the primary alcohol to an aldehyde followed by NaB2H4 or NaB3H4 reduction and hydrolysis of the protective groups yields erythro-D-[1-2H1]sphinganine or erythro-D-[1-3H1]sphinganine. The synthetic intermediates and isotopically labeled sphinganines are characterized by infrared analysis, 1H-nuclear magnetic resonance, optical rotation, and gas-liquid radiochromatographic and mass spectral fragmentation analyses. The [1-2H1] and [1-3H1] derivatives were obtained with overall yields (and isotope enrichments) of 11% (min. 84 mol% 2H1) and 8% (60 mCi/mmol), respectively.