Synthesis of sphinosine relatives. Part 27. Synthesis and absolute configuration of 6-hydroxylated new ceramides in human skin, ceramides B, 4, 7 and 8

6R-Configuration was assigned to three new ceramides isolated from human skin such as ceramide B [1, (2S,3R,4E,6R)6-hydroxy-N-(30'-hydroxytriacontanoyl)-4-sphingenine], ceramide 8 [2, (2S,3R,4E,6R)-6-hydroxy-N-(tetracosanoyl)-4-sphingeninel]and ceramide 4 (3, (2S,3R,4E,6R)-6-hydroxy-N[(30'-Iinoleoyloxy)triacontanoyll-4-sphingenine). (6R,2'R)Configuration was given to another ceramide in human skin, ceramide 7 [4, (2S,3R,4E,6R,2'R)-6-hydroxy-N-(2'-hydroxytetracosanoyl)-4-sphingenine]. These assignments were made possible by enzymatic preparation of the enantiomers of 1-pentadecyn-3-ol and those of 2-hydroxytetracosanoic acid. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)