13732-34-8Relevant articles and documents
Oxidation of hydrazones by hypervalent organoiodine reagents: Regeneration of the carbonyl group and facile syntheses of α-acetoxy and α-alkoxy azo compounds
Barton, Derek H. R.,Jaszberenyi, Joseph Cs.,Liu, Wansheng,Shinada, Tetsuro
, p. 14673 - 14688 (2007/10/03)
Various hydrazone derivatives of α-keto esters were prepared. The carbonyl group was readily regenerated in high yield from phenylhydrazones through oxidative hydrolysis using hypervalent organoiodine(III) reagents either bis(trifluoroacetoxy)-iodobenzene (BTIB) in aqueous acetonitrile or hydroxy(tosyloxy)iodobenzene (HTIB) in chloroform. α-Acotxy phenyl- or methylazo compounds were readily synthesized by oxidation of the corresponding hydrazones with iodobenzene diacetate (IBDA) in dichloromethane or acetic acid. α-Methoxy phenyl- or methylazo compounds were also prepared by oxidation of the hydrazones in methanol. The mechanisms of the oxidation reactions are discussed.
Geometrical Isomerism of Phenylhydrazones of α-Keto Esters. II. p-Substituted Phenylhydrazones of Ethyl Pyruvate and 2,4-Dinitrophenylhydrazones of Some α-Keto Esters
Ishibashi, Fumihide,Nashima, Takeo,Nishino, Junko,Kobayashi, Ikuko,Ichihara, Yoshinori,et al.
, p. 73 - 76 (2007/10/02)
Each geometrical isomer of various substituted phenylhydrazones of ethyl pyruvate and 2,4-dinitrophenylhydrazones of some α-keto esters was isolated in a pure state.Partial isomerizations of the E-isomers of the former hydrazones to the Z-isomers took place by keeping solutions of the hydrazones in organic solvents containing C, H, and Cl in the dark.An E- or Z-structure was assigned to each molecule on the basis of IR and 1H NMR spectra.In all cases, isomers with higher Rf -values on a silica gel TLC (using benzene as a developing solvent) involved an intramolecular hydrogen bonding between the imino hydrogen and the ester carbonyl oxygen.Thus, the Z-structure was assigned.An E-structure was assigned to other isomers with lower Rf-values.The present assignment is, thus, entirely the same as that proposed in a previous investigation.
