ISSN:
0170-2041
Keywords:
Betulin, labeled with 13C and 2H
;
Triterpenes
;
Vegetable wax
;
Isotopes, stable
;
Ozonolysis
;
Methylenation
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Selective acetylation of 1 at C-28 afforded the monoacetate 2, which was oxidized to the 3-oxo compound 8. H,D exchange at C-2 in 8 followed by reduction with LiAlH4 led to [2-2H]-betulin (5). Reduction of 8 with NaBD4 or LiAlD4 yielded [3-2H]betulin (6) besides different amounts of the respective 3α-hydroxy compound 7. For the introduction of a CD2 or 13CH2 unit at C-29 betulin diacetate 4 was ozonolyzed to give the known compound 10, which was treated either with CD2Br2, Zn, and TiCl4 in THF to yield the [29-2H2] compound 11 or with [13C]methyltriphenylphosphonium iodide and potassium tert-butoxide to afford the [29-13C]-labeled compound 11. Solvolysis of 11 and 13 with methanol and potassium carbonate afforded the desired compounds [29-2H2]betulin (12) and [29-13C]betulin (14).
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.1991199101215
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