The Methyl Enol Ethers of Ethyl 2, 4‐Dioxopentanoate

Abstract

SummaryMethylation of ethyl 2,4-dioxopentanoate with diazomethane gives a mixture of two enol ethers, the 2-methoxy and the 4-methoxy isomer, with a product ratio which depends upon reaction temperature. Both enol ethers, initially (2)-configurated, isomerize to the corresponding (E)-conformers, the 4-methoxy compound with particular ease.

Preparation and Novel Coordination Structure of [Cu(sacch)2(H2O)2] · 4 H2O

“…in 1982 HAIDER et al studied X-ray crystal structures of [M(sacch)z(H20)4] . 2 HzO, where M = Fe(II), Co(II), Ni(II), and Cu(I1) (HAIDER et al 1983). Saccharin interacts with metal elements in human body and effects on human health.…”

“…Moreover, the geometry of the coordination polyhedron of the hexa-coordinated copper atom is essentially a (4 + 2)-elongated octahedron. The fact that a pair of the Cu-0, (2.489 A) is extremely long suggests that this bond is much weaker than the shorter pair of metal-oxygen bonds (1.956-2.159 A) (HAIDER et al 1983), so it might be replaced by other strong ligands easily.…”