70771-86-7Relevant academic research and scientific papers
Superelectrophilic intermediates in the synthesis of novel indenole derivatives via 1,5-cyclization reactions of 5-aryl-1-azapenta-1,4-dien-3-ones
Ghavtadze, Nugzar,Froehlich, Roland,Bergander, Klaus,Wuerthwein, Ernst-Ulrich
experimental part, p. 3397 - 3406 (2009/05/26)
Oximes of 5,5-disubstituted 1-azapenta-1,4-dien-3-ones 3 underwent 1,5-cyclization reactions yielding indenole derivatives 4 in moderate to good yields upon treatment with an excess of trifluoromethanesulfonic acid. Similarly, the hydrazone 3g led to indenole 4f upon protonation. The reaction could also be successfully applied to the synthesis of benzo[b]cyclopenta[d] thiophene 5 starting from 3f. Products of a competing aza-Nazarov reaction were not observed. The reaction mechanism is explained by assuming the involvement of dicationic intermediates, generated by superelectrophilic solvation, similar to that of known Nazarov and aza-Nazarov-type transformations. Quantum chemical calculations of reaction energies and activation barriers are discussed with respect to the experimental results. Georg Thieme Verlag Stuttgart.
α-N-HYDROXYAMINO ACID DERIVATIVES
Kolasa, Teodozyj,Sharma, Sushil K.,Miller, Marvin J.
, p. 5431 - 5440 (2007/10/02)
Reactions of organolithium reagents with glyoxylate derived oximes provided a direct route to α-N-hydroxyamino acids.The process required direct attachment of an ionizable group to the glyoxylate carbonyl to prevent competitive reactions.The procedure allowed for direct formation of the α-chiral center of the newly formed α-N-hydroxyamino acid derivative.Introduction of potential chiral auxiliaries on the oxime oxygen resulted in modest diastereoselection.In most instances, use of chiral glyoxylamides also gave low diastereoselectivity.
