63546-29-2Relevant academic research and scientific papers
Vanadium-controlled crystallization of stereoisomers of NBu 4[VO2(N-salicylidene-isoleucinato)] through epimerization
Krivosudsky, Lukas,Schwendt, Peter,Simunek, Jan,Gyepes, Robert
, p. 8872 - 8875 (2014)
Reported herein is a simple synthetic and crystallization procedure for sequential isolation of two stereoisomers of isoleucine-derived vanadium(V) complexes from a racemic mixture with three stereogenic centers and therefore eight hypothetical species. The products of this crystallization were characterized by electronic and vibrational circular dichroism, NMR spectroscopy, and polarimetry to compare the chiroptic properties of the enantiomerically pure analogues prepared from L-isoleucine and D-allo-isoleucine. NMR studies pointed to the yet unobserved phenomenon of vanadium-catalyzed epimerization of isoleucine. Vanadium-controlled resolution of stereoisomers: NBu4[VO2(N-salicylidene-L-isoleucinato)] is the first product of crystallization from a mixture containing Schiff bases derived from racemic isoleucine and vanadate accessible as a pure compound. Vanadium-catalyzed epimerization of isoleucine was observed in the solutions of [VO2(N-salicylidene-isoleucinato)]- complexes (see figure).
