ISSN:
0170-2041
Keywords:
1,2-Didehydroprolines
;
Oxime reduction
;
Ornithine derivatives
;
Butyronitriles
;
2-Piperidones
;
Proline derivatives
;
Amino acids
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Ring-Opening Reactions of 1,2-Didehydroprolines, I. - Synthesis of 4-Hydroxyornithine and Protected 4-Amino-3-hydroxybutyronitrilesThe cyclic azomethines 6a, b, d and f easily undergo ringopening reaction with hydroxylamine and its O-alkyl derivatives leading to the oximino compounds 3a, b, d and f-i. Dissolved alkali metals in amines (Birch conditions) give satisfactory yields of reduction products with a stereochemistry depending on the substitution pattern in 3b, d, f-i. In case of 3d, the (2R,4R) stereoisomer 9b is the sole product, which can subsequently be cleaved to give 8b. Compounds 3g-i give predominantly the (2S,4R) product 8a. Acylation under alkaline conditions decarboxylates the oximino compounds 3b and d to the corresponding protected butyronitriles 14a-h. Trifluoroacetic anhydride transforms 3b into the nitrile 14i together with the cyclization product 15.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.1992199201205
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