Biomedical subjects

Hannes Neukirch

Publications and source records attributed to Hannes Neukirch.

5 recordsLinked to original sources

PubMed2005

A halogen-bonding-based heteroditopic receptor for alkali metal halides.

A new heteroditopic receptor for alkali metal halides has been designed and synthesized. It is comprised of a well-established motif for cation binding and a motif for halogen-bonding-based anion recognition processes. The single-crystal X-ray structure of the complex between the heteroditopic receptor and sodium iodide is reported. Thanks to the cooperativity of metal coordination and the strong I-...I halogen bonding, the ion pair is fully separated. The boosting effect of the binding of the anion through halogen bonding on the coordination of the cation by the receptor has been proved also in solution by NMR experiments. The selectivity of the new heterotopic receptor toward different alkali metal halides has been tested by ESI mass experiments.

Journal Article↗

PubMed2005

Spontaneous resolution in a halogen bonded supramolecular architecture.

The halogen bonding driven self-assembly of 1,8-diiodoperfluorooctane and N,N,N',N'-tetramethyl-p-phenylenediamine induces the formation of a chiral and enantiopure co-crystal wherein the fluorinated chains adopt an unusual gauche arrangement.

Journal Article↗

PubMed2005

Halogen bonding based recognition processes: a world parallel to hydrogen bonding.

Halogen bonding is the noncovalent interaction between halogen atoms (Lewis acids) and neutral or anionic Lewis bases. The main features of the interaction are given, and the close similarity with the hydrogen bonding will become apparent. Some heuristic principles are presented to develop a rational crystal engineering based on halogen bonding. The focus is on halogen-bonded supramolecular architectures given by halocarbons. The potential of the interaction is shown by useful applications in the field of synthetic chemistry, material science, and bioorganic chemistry.

Journal Article↗

PubMed2003

Parthenolide and its photochemically synthesized 1(10)Z isomer: chemical reactivity and structure-activity relationship studies in human leucocyte chemotaxis.

The present study has achieved the photochemical conversion of a germacrolide into a melampolide. The investigation on their chemical properties allowed us to evaluate the minimum interatomic distance needed for transannular bridging of C(10) ring in germacrolides and to explain the regiochemical selectivity of electrophilic cyclizations. The antiinflammatory activity of parthenolide and its semisynthetic derivatives was evaluated by in vitro chemotaxis assay with human neutrophiles. These structure-activity relationship studies have led to hypothesize a new pharmacophore and have provided useful information for computationally designed drugs.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMedDate not supplied

Simultaneous quantitative determination of eight triterpenoid monoesters from flowers of 10 varieties of Calendula officinalis L. and characterisation of a new triterpenoid monoester.

Dichloromethane extracts of dried flowers of Calendula officinalis contain eight known bioactive triterpendiol monoesters, namely, faradiol-3-O-palmitate, faradiol-3-O-myristate, faradiol-3-O-laurate, arnidiol-3-O-palmitate, arnidiol-3-O-myristate, arnidiol-3-O-laurate, calenduladiol-3-O-palmitate and calenduladiol-3-O-myristate. These pentacyclic terpenoids have been quantified simultaneously using reversed-phase HPLC with isocratic elution and internal standardisation. Of the 10 varieties of C. officinalis investigated, Calypso Orange Florensis produced the highest amounts of the bioactive monoesters, followed by Fiesta Gitana Gelb and May Orange Florensis. The lipophilic extract from the flowers of Calypso Orange Florensis variety also contained low levels of the newly characterised calenduladiol-3-O-laurate.

Calendula↗