Synthesis of two unique compounds, a ceramide and a cerebroside, occurringin human stratum corneum

The cerebroside 1a and the ceramide 1b, both playing important roles in epi dermal barrier function, were synthesized by N-acylation of 1-O-glucosylate d C-18-sphingosine 2 and C-18-sphingosine 8, respectively, with O-acyl fatt y acid 3. The required compound 3 was obtained from omega -hydroxy fatty ac id 6 and linoleic acid 7 by esterification. The omega -hydroxy C-30-fatty a cid 6 was prepared as follows: Copper-catalyzed coupling of omega -hydroxy alkyl halide 11 with the Grignard reagent derived from bromo compound 13 af forded after oxidation C-17-aldehyde 15. Wittig reaction with phosphonium s alt 10, derived from omega -bromo-tridecanoic acid 9, and subsequent hydrog enation and O-deprotection furnished 6 in high yield.