Ferdinand Bohlmann

Bio: Ferdinand Bohlmann is an academic researcher from Technical University of Berlin. The author has contributed to research in topics: Germacranolide & Labdane. The author has an hindex of 51, co-authored 1492 publications receiving 25091 citations. Previous affiliations of Ferdinand Bohlmann include Plovdiv University "Paisii Hilendarski" & Shahid Beheshti University.

Lupinen‐Alkaloide, VIII. Zur Konfigurationsbestimmung von Chinolizidin‐Derivaten

Abstract: Es wird eine charakteristische Bandengruppe im IR-Spektrum beschrieben, die in Piperidinderivaten nur dann auftritt, wenn mindestens zwei nachbarstandige axiale CH-Bindungen in trans-Stellung zum einsamen Elektronenpaar am Stickstoff stehen. Dies ist z. B. in trans-Chinolizidin-Ringen der Fall, aber nicht, wenn, durch Konstitution und Konfiguration eines Molekuls bedingt, ein cis-Chinolizidin-Ringsystem vorliegt. Durch Synthese deuterierter Basen last sich die fragliche Bandengruppe eindeutig zuordnen.

13C-NMR-Spektren von Monoterpenen

Abstract: Die 13C-NMR-Spektren von fast 100 Monoterpenen zeigen, das sie zur Charakterisierung derartiger Verbindungen sehr brauchbar sind. Besonders wertvoll ist diese Methode zur Klarung stereochemischer Probleme. Bis auf wenige Falle folgen die beobachteten chemischen Verschiebungen den allgemeinen Regeln. Die Probleme der Messungen mit Verschiebungsreagenzien werden diskutiert. The 13C NMR spectra of nearly 100 monoterpenes show that they are very useful for the characterisation of these compounds. This method is especially valuable for the elucidation of stereochemical problems. With the exception of a few cases the observed chemical shifts follow the common rules. The problems with measurements using shift reagents are discussed.

Ionic Liquids-New "Solutions" for Transition Metal Catalysis.

Abstract: Ionic liquids are salts that are liquid at low temperature (<100 degrees C) which represent a new class of solvents with nonmolecular, ionic character. Even though the first representative has been known since 1914, ionic liquids have only been investigated as solvents for transition metal catalysis in the past ten years. Publications to date show that replacing an organic solvent by an ionic liquid can lead to remarkable improvements in well-known processes. Ionic liquids form biphasic systems with many organic product mixtures. This gives rise to the possibility of a multiphase reaction procedure with easy isolation and recovery of homogeneous catalysts. In addition, ionic liquids have practically no vapor pressure which facilitates product separation by distillation. There are also indications that switching from a normal organic solvent to an ionic liquid can lead to novel and unusual chemical reactivity. This opens up a wide field for future investigations into this new class of solvents in catalytic applications.

Structure of Graphite Oxide Revisited

Abstract: Graphite oxide (GO) and its derivatives have been studied using 13C and 1H NMR. NMR spectra of GO derivatives confirm the assignment of the 70 ppm line to C−OH groups and allow us to propose a new structural model for GO. Thus we assign the 60 ppm line to epoxide groups (1,2-ethers) and not to 1,3-ethers, as suggested earlier, and the 130 ppm line to aromatic entities and conjugated double bonds. GO contains two kinds of regions: aromatic regions with unoxidized benzene rings and regions with aliphatic six-membered rings. The relative size of the two regions depends on the degree of oxidation. The carbon grid is nearly flat; only the carbons attached to OH groups have a slightly distorted tetrahedral configuration, resulting in some wrinkling of the layers. The formation of phenol (or aromatic diol) groups during deoxygenation indicates that the epoxide and the C−OH groups are very close to one another. The distribution of functional groups in every oxidized aromatic ring need not be identical, and both ...

Controlled microwave heating in modern organic synthesis.

Abstract: Although fire is now rarely used in synthetic chemistry, it was not until Robert Bunsen invented the burner in 1855 that the energy from this heat source could be applied to a reaction vessel in a focused manner. The Bunsen burner was later superseded by the isomantle, oil bath, or hot plate as a source for applying heat to a chemical reaction. In the past few years, heating and driving chemical reactions by microwave energy has been an increasingly popular theme in the scientific community. This nonclassical heating technique is slowly moving from a laboratory curiosity to an established technique that is heavily used in both academia and industry. The efficiency of "microwave flash heating" in dramatically reducing reaction times (from days and hours to minutes and seconds) is just one of the many advantages. This Review highlights recent applications of controlled microwave heating in modern organic synthesis, and discusses some of the underlying phenomena and issues involved.