A short and efficient stereoselective synthesis of all four diastereomers of sphingosine

Characterization of overall ceramide species in human stratum corneum

“…In addition, this study indicates that another characteristic of CERs in the SC is that the species have longer chain lengths, especially in sphingoids, than do those of other cells/tissues, including hair. This is exemplified by the facts that CER [NS] in the SC is composed of C [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] N and C [16][17][18][19][20][21][22][23][24][25][26] [16][17][18][19][20] DS (16). This characteristic may be necessary to maintaining the barrier function of human skin, possibly because CER species with longer chain lengths seem to be appropriate for preventing water from diffusing from the SC to the outside, or for preventing chemicals from penetrating from the outside to the SC.…”

“…Those authentic CERs were synthesized by coupling corresponding fatty acids and sphingoids in the presence of 1-ethyl-3-(3-diethylaminopropyl)carbodiimide hydrochloride, with 1-hydroxybenzotriazole as the coupling reagent (25). Constitutional fatty acids, except for hexacosanoic acid and linoleic acid, and sphingoids were prepared according to the literature (26)(27)(28)(29)(30)(31). Each of the authentic CERs synthesized was purified with flash silica-gel column chromatography and/or recrystallization.…”

Straightforward Access to Protected syn α‐Amino‐β‐hydroxy Acid Derivatives

“…Indeed, (2S,3S)-azidosphingosine (10 g) can be obtained efficiently (58 % yield) from 1 after the aldol reaction and subsequent reduction (temporary protection of the hydroxy group is required to obtain good yields). [16] Reduction of the azido group by classical Staudinger reaction conditions should lead to known l-threo-sphingosine, [17] thereby illustrating that this aldol reaction represents one of the simplest and most efficient methods, reported so far, for the synthesis of a sphingosine core. [18] As another example, we used 4 c (R = p-NO 2 Ph) for the synthesis of amino alcohol 12 c, the enantiomer of a known precursor of the antibiotic chloramphenicol (Scheme 4).…”

Straightforward Access to Protected syn α‐Amino‐β‐hydroxy Acid Derivatives

“…Indeed, (2 S ,3 S )‐azido‐sphingosine ( 10 g ) can be obtained efficiently (58 % yield) from 1 after the aldol reaction and subsequent reduction (temporary protection of the hydroxy group is required to obtain good yields) 16. Reduction of the azido group by classical Staudinger reaction conditions should lead to known L ‐ threo ‐sphingosine,17 thereby illustrating that this aldol reaction represents one of the simplest and most efficient methods, reported so far, for the synthesis of a sphingosine core 18…”