ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The sphingolipids 1a, b and 2a, b which play important roles in epidermal barrier function, were synthesized by N-acylation of C18-sphingosine 3 and 1-O-glucosylated C18-sphingosine 6, respectively, with ω-acyloxy-substituted fatty acids 4 and 5 (Scheme 1). These fatty acids were obtained from ω-hydroxy-substituted fatty acids 8 and 9 by esterification with linoleic acid (7). The C34-fatty acid 8 was prepared as follows: C25-Compound 18 was obtained by means of a Wittig reaction of C13-aldehyde 13 with C12-phosphonium salt 15 or of C12-aldehyde 24 with C13-phosphonium salt 21, respectively, and subseqent hydrogenation and O-deprotection (Scheme 2). Alternatively, 8 was prepared via 30 by copper-catalyzed coupling of C13-alkyl halide 19 with the Grignard reagent derived from C12-alkyl bromide 14 (Scheme 2). Oxidation of 18 to aldehyde 39 and Wittig reaction with C9-phosphonium salt 41 furnished the desired ω-hydroxy-substituted fatty acid 8, after O-deprotection (Scheme 3). Similarly, Wittig reaction of C11-phosphonium salt 22 with C12-aldehyde 24 furnished C23-aldehyde 40, after hydrogenation, O-deprotection, and oxidation; Wittig reaction with compound 41 and subsequent deprotection afforded the desired C32-fatty and 9 (Scheme 3). an alternative strategy furnished compound 8 by a coupling reaction of alkyne 53 with ω-bromo-substitued fatty acid 52, obtained from compounds 24 and 47 by Wittig reaction, hydrogenation, and introduction of bromide (Scheme 4). Hydrogenation (Lindlar's catalyst) of the resulting C34-alkyne 54 and deprotection furnished 8.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19930760141
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