146952-05-8Relevant articles and documents
Ring-Opening Reactions of 1,2-Didehydroprolines, I. - Synthesis of 4-Hydroxyornithine and Protected 4-Amino-3-hydroxybutyronitriles
Haeusler, Johannes
, p. 1231 - 1238 (2007/10/02)
The cyclic azomethines 6a, b, d and f easily undergo ring-opening 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 tranforms 3b into the nitrile 14i together with the cyclization product 15.Key Words: 1,2-Didehydroprolines / Oxime reduction / Ornithine derivatives / Butyronitriles / 2-Piperidones / Proline derivatives / Amino acids
