Studies on the biosynthesis of the antibiotic reductiomycin in Streptomyces xanthochromogenus
作者:Hyeongjin Cho、John M. Beale、Cynthia Graff、Ursula Mocek、Akira Nakagawa、Satoshi Omura、Heinz G. Floss
DOI:10.1021/ja00079a009
日期:1993.12
The biosynthesis of the antibiotic reductiomycin (I) in Streptomyces xanthochromogenus was investigated by feeding experiments with radioactive and stable isotope-labeled precursors. NMR and mass spectroscopic analyses of the labeled I samples revealed that the acetoxy group comes from acetate, the 2-amino-3-hydroxycyclopent-2-enonemoiety arises by a novel intramolecular cyclization of 5-aminolevulinic
NMR studies of hindered rotation and thermal decomposition of novel 1-aryl-3,3-dialkyltriazenes
作者:Th. Lippert、A. Wokaun、J. Dauth、O. Nuyken
DOI:10.1002/mrc.1260301206
日期:1992.12
thermostability of these compounds was investigated by differential scanning calorimetry; activation energies of 240–280 kJ mol−1 were determined for the thermal decomposition. The hinderedrotation of the dialkylamino group was studied by 1H NMR exchange measurements. Both experiments are interpreted in terms of an involvement of a 1,3‐dipolar structure of the NNN functional group. The influence of substituents