The synthesis of galactose clusters that are linked to a steroid moiety by a peptide-like spacer unit is described. The galactose cluster is obtained by Koenigs-Knorr glycosylation of TRIS-Gly-Fmoc (2b) under Helferich conditions. Peptide and ester bonds are formed after activation of carboxylic acids as diphenylthiophene dioxide (TDO) esters. 6a is synthesized in a convergent way by coupling of (Ac4Gal)3-TRIS-Gly (3e) with cholesteryl TDO succinate (5b). Coupling of (Ac4Gal)3-TRIS-Gly hydrogen succinate (3f) with Gly-O-Chol (5d) by means of EEDQ yields 6d. Reaction of (Ac4Gal)3-TRIS-Gly-SUCC-O-TDO (3g) with 25-hydroxycholesterol leads in a linear sequence to the oxysterol derivative 6f. Selective cleavage of the acetyl groups from galactose units yields the known compound 6b and the new derivatives 6e and 6g.
| Identifer | oai:union.ndltd.org:Potsdam/oai:kobv.de-opus-ubp:1678 |
| Date | January 1990 |
| Creators | Peter, Martin G., Boldt, Peter C., Niederstein, Yvonne, Jasna Peter-Katalinić |
| Publisher | Universität Potsdam, Mathematisch-Naturwissenschaftliche Fakultät. Institut für Chemie, Extern. Extern |
| Source Sets | Potsdam University |
| Language | German |
| Detected Language | English |
| Type | Postprint |
| Format | application/pdf |
| Source | Liebigs Annalen der Chemie, 9 (1990), S. 863-869 - ISSN 1099-0690; 0170-2041 |
| Rights | http://opus.kobv.de/ubp/doku/urheberrecht.php |
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