1H- and 13C-NMR spectra of palladium and platinum meso-tetraphenylporphyrins

The ¹H- and ¹³C-NMR spectra of palladium and platinum mesotetraphenylporphyrins (TPP) are reported. PtTPP demonstrates spin-spin coupling between platinum and the pyrrole·β-protons and carbons. There is some evidence for spin-spin coupling between platinum and the pyrrole α-carbons. PdTPP and PtTPP also demonstrate upfield shifting of their pyrrole α-carbon ¹³C-resonances. Structural and electronic arguments are advanced to explain this behaviour.     

Qualitative mass spectrometric analysis of the total diterpene bases from the roots ofAconitum kusnezoffi

A quantitative analysis of the roots ofAconitum kusnezoffi has been made by a group of mass-spectrometric methods. Twelve diterpene bases have been studied of which ten have been identified as beiwutine, aconitine. mesaconitine, 3-deoxyaconitine, hypaconitine, neoline, songorine, isotalatisidine, talatisidine, and 10-hydroxyneoline.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 89–92, January–February, 1996. Original article submitted August 7, 1995.     

Reactivity of functional groups on the protein surface: development of epoxide probes for protein labeling

We present the development of new affinity probes for protein labeling based on an epoxide reactive group. Systematic screening revealed that an epoxide functionality possesses the special combination of stability and reactivity which renders it stable toward proteins in solution but reactive on the protein surface outside the active site (proximity-induced reactivity). Highly efficient and selective labeling of purified HCA II (human carbonic anhydrase II) was achieved. For instance, 2 equiv of epoxide probe 9 was sufficient for nearly quantitative labeling of HCA II (>90% yield, 20 h reaction time). MS analysis of the labeled protein revealed that 1 equiv of the probe was attached and that labeling occurred at a single residue (His 64) outside the active site. Importantly, epoxide probe 9 selectively labeled HCA II both in simple protein mixtures and in cellular extracts. In addition to the chemical insight and its relevance to many epoxide-containing natural products, this study generated a promising lead in the development of new affinity probes for protein labeling.     

Mass spectrometry of pennogenin glycosides

The electron-impact mass spectra of five unesterified pennogenin glycosides, which contain the M⁺ or (M - H₂O)⁺ peaks, have been obtained. The characteristic features of the fragmentation of these compounds have been studied. In addition to ions characterizing the successive elimination of carbohydrate units, fragments have been detected which show the breakdown of the terminal pyranose ring. Five new directions of the fragmentation of the spirostanol skeleton due to the presence of an OH group at C-17 have been found.Institute of the Chemistry of Plant Substance, Academy of Sciences of the Uzbek SSR, Tashkent. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Science Center of the Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 337–341, May–June, 1986.