Hawaiian plant studies. XIV. Alkaloids of Ochrosia sandwicensis A. Gray

Two quaternary alkaloids were isolated from Ochrosia sandwicensis A. Gray. One was shown to be hunterburnine -methochloride (I), while the other has been named ochrosandwine and its probable structure is 10-hydroxydihydrocorynantheol methochloride (II). The stereochemistry of the related alkaloid huntrabrine methochloride (IV) is elaborated. Two previously isolated yellow Ochrosia bases were shown to be ellipticine hydrochloride and methoxyellipticine for which the structure-8-methoxyellipticine (V) is suggested. A rapid separation of alkaloids from plant material is described, which involves extraction with hot dilute acetic acid, precipitation with Mayer's reagent and conversion of the complex to the chlorides by anion exchange.     

A Complex Pyrrolo-oxazinone and Its Iodo Derivative Isolated from a Tunicate

Two cytotoxic triphenylpyrrolo-oxazinones were isolated from a tunicate and their structures elucidated by spectral methods. Lukianol A ( = 3,7,8-tris(4-hydroxyphenyl)pyrrolo[2,1-c][1,4]oxazin-1 (1H)-one; 1 ) had MIC of 1 μg/ml in KB cytotoxicity tests; MIC value for 2 was 100 μg/ml.     

Alternativ-Liganden. IV. Darstellung von Chelatliganden des Typs Me2XSiMe2CH2X′Me2 (Me = CH3; X,X′ = N,P und/oder As)

Preparation of Chelating Ligands of the Type Me₂XSiMe₂CH₂X′Me₂ (Me = CH₃; X, X′ = N, P and/or As) Chelating Ligands of the general type Me₂XSiMe₂CH₂X′Me₂ (Me = CH₃; X, X′ = N, P As) are obtained from ClSiMe₂CH₂Cl by the following reactions (see “Inhaltsübersicht”). The new compounds have been characterized by analytical and spectroscopic methods (IR, NMR, MS).     

Mamanine and pohakuline,two unprecedented quinolizidine alkaloids from sophorachrysophylla

From the bark of the endemic Hawaiian tree Sophora chrysophylla Seem. we have isolated two unprecedented quainolizidine alkaloids, mamanine (4) and pohakuline (5). Both bases are 1-hydroxymethylenequinolizidines which are linked at C-3 to α-pyridone or α-piperidone moieties. The alkaloids may be intermediates in a heretofore unknown biogenetic pathway of Sophora alkaloids.     

Co-occurrence of two terpenoid isocyanide-formamide pairs in a marine sponge (Halichondria sp.)

From a marine sponge (Halichondria sp.) we have isolated amorphane sesquiterpenoids that are substituted at C-10 by isocyanide (1), formamide (2), and isothiocyanate (3), and diterpenoids that are 3,7,11,15- tetramethyl-1,6,10,14-hexadecatetraenes (geranyllinaloyl) bearing isocyanide (13), formamide (14), and isothiocyanate (16) functions at C-3.     

5α-24-Norcholestan-3β-ol and (24Z)-Stigmasta-5,7,24(28)-trien-3β-ol,Two New Marine Sterols from the Pacific Sponges Terpios zeteki and Dysidea herbacea

The steroidal components of 2 marine sponges, Terpios zeteki (from Hawaii) and Dysidea herbacea (from Australia) were fractionated through a combination of chromatographic methods, including reversed phase HPLC., and were analyzed by a combination of physical methods, including high resolution GC.-MS. and 360 MHz ¹H-NMR. T. zeteki contains 6 conventional 5α-stanols which comprise 91% of the sterol mixture, and traces (0.5%) of a new C₂₆ sterol, 5α-24-norcholestan-3β-ol. Minor amounts of conventional Δ⁵-sterols (6.5%) and of a single Δ⁴-3-ketosteroid (1.5%) were also present. In contrast, the Australian sponge (D. herbacea) contains 3 Δ^5,7-sterols which comprise 1.5% of the sterol mixture, and one new C₂₉ sterol, (24 Z)-stigmasta-5,7,24(28)-trien-3β-ol, as the major component (75%). In addition, minor amounts of conventional 5α-stanols (0.5%), Δ⁵-sterols (5%) and 5α-Δ⁷-sterols (18%) were present in this complex sterol mixture. The possible dietary or endosymbiotic origins of these sterols are discussed.     

Autocollimation spectroscopy for fast hydrogenic ions

We propose a new experimental method (Autocollimation Spectroscopy), which provides a strong suppression of systematic error contributions in the laser resonance spectroscopy of broad resonances. Using a bidirectional laser beam with a fixed wavelength in connection with high current pulsed ion beams an accuracy ofΔE _Exp/Γ≈5·10^?5 (Γ: resonance width) for the resonance energy seems to be achievable. Applying this technique to 2S-Lamb shift (LS) measurements on medium heavy ions would yield a precision ofΔE _Exp/E _LS≈1·10^?5, i.e. an improvement by a factor up to 100 as compared to present experiments.     

Poly(acrylate‐b‐styrene‐b‐isobutylene‐b‐styrene‐b‐acrylate) Block Copolymers via Carbocationic and Atom Transfer Radical Polymerizations

A series of polyacrylate‐polystyrene‐polyisobutylene‐polystyrene‐polyacrylate (X‐PS‐PIB‐PS‐X) pentablock terpolymers (X=poly(methyl acrylate) (PMA), poly(butyl acrylate) (PBA), or poly(methyl methacrylate) (PMMA)) was prepared from poly (styrene‐b‐isobutylene‐b‐styrene) (PS‐PIB‐PS) block copolymers (BCPs) using either a Cu(I)Cl/1,1,4,7,7‐pentamethyldiethylenetriamine (PMDETA) or Cu(I)Cl/tris[2‐(dimethylamino)ethyl]amine (Me₆TREN) catalyst system. The PS‐PIB‐PS BCPs were prepared by quasiliving carbocationic polymerization of isobutylene using a difunctional initiator, followed by the sequential addition of styrene, and were used as macroinitiators for the atom transfer radical polymerization (ATRP) of methyl acrylate (MA), n‐butyl acrylate (BA), or methyl methacrylate (MMA). The ATRP of MA and BA proceeded in a controlled fashion using either a Cu(I)Cl/PMDETA or Cu(I)Cl/Me₆TREN catalyst system, as evidenced by a linear increase in molecular weight with conversion and low PDIs. The polymerization of MMA was less controlled. ¹H‐NMR spectroscopy was used to elucidate pentablock copolymer structure and composition. The thermal stabilities of the pentablock copolymers were slightly less than the PS‐PIB‐PS macroinitiators due to the presence of polyacrylate or polymethacrylate outer block segments. DSC analysis of the pentablock copolymers showed a plurality of glass transition temperatures, indicating a phase separated material.     

N,N-dimethylamino-3-guaiazulenylmethane from a deep sea gorgonian

A naturally occurring nitrogeneous azulene derivative (4) has been isolated from a deep sea gorgonian collected by minisubmersible at -350 m.     

K+P elastic scattering at 32 GeV/c

Elastic scattering of 32.1 GeV/c K⁺ on protons has been measured in a bubble chamber experiment. Results are presented in the momentum transfer interval 0.06–1.40 GeV² and compared with data at different energies. An effective Regge trajectory is calculated using K⁺p elastic data from 10 to 175 GeV/c.