Jürgen-Hinrich Fuhrhop

THE PHOTOOXYGENATION OF MAGNESIUM‐OCTAETHYLPORPHIN*

Abstract— Octaethylporphinato‐magnesium (MgOEP) has been photooxygenated in quantitative yield to a brown compound with its main absorption peaks at 825 and 408 nm. The product has been isolated and evidence suggests that it is 4‐formyl‐5‐oxa‐octaethylporphinato‐magnesium II. II is very labile to hydrolysis, the main isolated decomposition product being 1, γ‐dioxo‐8‘‐formyl‐octaethyl violin III. The absorption, i.r., PMR and mass spectra of II and III are reported and possible paths to their formation are discussed.

Molecular and crystal structure of the bola-amphiphile N-[8-(d-gluconamido)octyl]-d-gluconamide

Abstract The crystal structure of the title compound [ 5 ; space group P 2 1 ; a = 8.375(5), b = 51.52(2), c = 5.6473(3) A; β = 89.64(4)°] was determined by X-ray diffraction methods and refined to R = 0.107. There are two molecules in the asymmetric unit, which adopt nearly identical conformations. Each molecule has two parts that differ only in the torsion angle N-C-7-C-8-C-9, which can be synclinal (−64°) or anti (168°). The molecules are arranged in sheets and the packing is stabilised by strong intra- and inter-molecular hydrogen bonds, some of which form a homodromic arrangement.

Bolaamphiphiles with mannose- and tetraalkylammonium head groups as coatings for nucleic acids and possible reagents for transfections

Abstract Tetralkylammonium salts with a long hydrolyzable chain and a terminal bromine atom or amino group have been prepared. The bromine was then substituted by thiomannose, the amine amidated with a mannopyranosyl-gluconolactone. The resulting bolaamphiphiles with a positively charged tetraalkylammonium and an electroneutral mannose head group each were used to cover negatively charged nucleic acids quantitatively with an electroneutral mannose coat. The aggregates were characterized by intercalation experiments and electron microscopy. A tritium labelled amphiphile coat containing 32 P-labelled t-RNA was taken up by macrophages, uncoated t-RNA was not. The coated nucleic acids should be of general use in transfections.

Metalloporphyrin-catalyzed oxidations [1] 2. Inhibition and re-activation of metalloporphyrin catalysts. A simple model for hormone action

Abstract Cobalt(III) and iron(III) porphyrins have been found to catalyse the autoxidation of cyclohexene to allylic hydroperoxides which then decomposed to give 2-cyclohexenone as the main product. If molybdenum of vanadium complexes (porphyrinates of acetylacetonates) were added in equimolar amounts to the cobalt or iron porphyrins, the reaction was stopped. Addition of steroids, deazaflavin or chrysene, led to a re-activation of the iron and cobalt porphyrin catalysts. With lanosterol equimolar amounts were sufficient to produce this effect. The main oxidation product of cyclohexene was again 2-cyclohexenone. Reactivation could also be achieved with high concentrations of cumene. In this case a 1|1 mixture of cyclohexane epoxide and 2-cyclohexenol were formed. The possible bearing of the findings on the action of steroid hormones in nature is briefly discussed.

ESR studies of metal complexes and Pi-radicals of biliverdin derivatives

Abstract ESR investigations are reported for the copper, nickel, and palladium complexes of some open-chain tetrapyrr ole ligands. The ESR spectra of Cu(II) complexes of octaethylformylbiliverdin (OEFB) and Ni complexes of OEFB, biliverdin (BVD), mesobiliverdin (MBVD), and dioxo-octamethylbilatriene (OAS) and the Pd complex of (OAS) have been recorded in liquid crystal and chloroform solutions. For Cu(OEFB), the ESR parameters (measured at 100°K), which fit an axially symmetric spin Hamiltonian, are: g ⊥ = 2.029, g ∥ = 2.174, A ⊥ Cu = 37.22 × 10 −4 cm −1 , A ∥ Cu = 171.7 × 10 −4 cm −1 , A ⊥ N(SUHP) = 16.66 × 10 −4 cm −1 , A ∥ C(SUHP) = 13.33 × 10 −4 cm −1 . By a comparison of these parameters with model square planar and tetrahedral systems, it is inferred that the ligand field in Cu(OEFB) deviates only moderately from planarity and that the ligand in the complex exists as a single-turn helix. Calculation of m.o. coefficients from the ESR parameters also supports this view. The Ni and Pd complexes of the bilatrienes have yielded ESR signals of free radical type in chloroform solutions at room temperature. The isotropic g values are close to that of the electrogenerated pi-radical of the free ligand OAS ( g = 2.0023). At 100°K, the Ni and Pd complexes exhibit g -anisotropy ( g ∥ = 2.012, g ∥ = 1.982 for Ni(OEFB)). From the trends in the g tensors ( g ∥ > g ∥ ), it is concluded that the free radicals obtained from the above Ni complexes possess a small fraction of Ni(III) character. The ligand field in these complexes is suggested to be similar to that of Cu(OEFB). Some comments on the possible relation to the phytochrome problem are given.

Die Strukturen der essentiellen ungesättigten Fettsäuren, Kristallstruktur der Linolsäure sowie Hinweise auf die Kristallstrukturen der α-Linolensäure und der Arachidonsäure / The Structures of the Essential Unsaturated Fatty Acids. Crystal Structure of Linoleic Acid and Evidence for the Crystal Structures of α-Linolenic Acid and Arachidonic Acid

Abstract The essential fatty acids linoleic, α-linolenic and arachidonic acid have been crystallized for the first time. The crystal and molecular structures have been elucidated by X-ray analysis. Linoleic acid crystallizes monoclinic P21/c with a = 4298(3), b = 463.2(3), c = 937.7(6) pm, β = 109.38(8)°, Z = 4. The closely packed molecules are stretched with a tttttts̄CssCs̄tt conformationa. By comparison of the unit-cell constants and calculated densities of the unsaturated fatty acids it may be shown that both α-linolenic acid and arachidonic acid also possess stretched structures in the crystal lattice, α-linolenic acid must display a tttttts̄CssCs̄s̄Cs and arachidonic acid a tts̄CssCs̄s̄CssCs̄ttt conformation.

Conformational studies of polymorphic N-octyl-D-gluconamide with 15N (labeled) 13C (natural abundance) REDOR spectroscopy

Magnetic dipolar couplings between the 15N atom (labeled) and neighboring 13C atoms (natural abundance) in three solid modifications of N-octyl-D-gluconamide are measured with rotational echo double resonance (REDOR). A unique spectral assignment of 13C resonances is possible by means of their dipolar dephasing. While in the monolayer crystal and in the fiber modification the assignment is amenable to the solution spectra, in the bilayer crystallites a different assignment is found. The dipolar couplings in the range 45 to 1220 Hz are converted into CN distances. These distances are employed in conjunction with the 13C chemical shieldings of the CP-MAS spectra to determine sets of possible torsion angles, which define the molecular conformation in the neighborhood of the amide group. In contrast to the monolayer crystal, for the fiber and bilayer crystallite modifications a gauche bend at the C2–C3 bond is found, giving the molecules the shape of a 2G sickle.

Quantitative analysis of trifluoroacetic acid in body fluids of patients treated with halothane

A simple procedure for the quantitative analysis of trifluoroacetic acid (TFA) in urine and serum from patients narcotized with halothane is described. This involves addition of sodium hydroxide to the body fluid, evaporation of the aqueous phase and esterification of TFA in concentrated sulphuric acid with 2,2,2-trichloroethanol. The gaseous phases above the reaction mixture were then analyzed by gas chromatography with a nickel-63 electron-capture detector. The detection limit was 1 microgram of TFA per mililitre of body fluid (200 microgram of body fluid are analysed) and the relative standard deviation was +/-6%. Patients treated with ethrane, another commercial anaesthetic, did not produce any detectable TFA.

The X-ray crystal structure of N-(1-octyl)-d-talonamide and a consideration of its hydrogen-bonding scheme

Abstract The crystal structure of N -(1-octyl)- d -talonamide [space group P 2 1 2 1 2 1 , a = 914.0(2), b = 581.4(1), c = 6257(1) pm] shows two independent molecules in the asymmetric unit. The oligomethylene chains of both molecules are extended. The talonic acid moieties have a gauche -bend along C-1C-2C-3C-4 thereby avoiding a 1,3- syn interaction (O|O)_between O-2 and O-4, whereas the resulting C|O orientation between C-1 and O-4 is tolerated. The molecular packing is a symmetric tail-to-tail bilayer sheet comparable to that of the diastereomeric gulonamide analogue, but in contrast to the head-to-tail packing in the gluconamide analogue. This experimental result is explained by the occurrence of different hydrogen-bond patterns between hydroxyl groups ( i ) of adjacent crystal sheets (talon- and gulon-amide derivative) or ( ii ) within one crystal sheet (gluconamide derivative).

Metalloporphyrin-catalyzed oxidations 3. Expoxidation and aldehyde formation by oxidative carboncarbon bond cleavage in squalene

Abstract Hemin dimethylester and cobalt(II/III) octaethylporphyrins have been found to catalyze the autoxidation of squalene, C30H50. Three isomeric epoxides and two α, β-unsaturated aldehydes with 27 and 25 carbon atoms were the main products (⩾=60% of the oxidation products). These compounds were isolated and characterized by various spectroscopic techniques. The use of cobalt(III) and iron(III) acetylacetonates as catalysts for squalene autoxidation led mainly to epoxides. With the low molecular weight analoque of squalene, 2-methyl-2-pentene, the cobalt(II/III) octaethylporphyrin-catalyzed autoxidation produced ketones and alcohols derived from allylic hydroperoxides. The differences are explained by aggregation phenomena.