Helvetica Chimica Acta

doi: 10.1002/hlca.19700530401pmid: N/A

Domb, S.; Schaffner, K.

doi: 10.1002/hlca.19700530402pmid: 5433433

In einer vorangehenden Arbeit (2) wurde gezeigt, dass sich das triplettangeregte α, β‐ungesättigte δ‐Diketon 1 in die beiden stereoisomeren Cyclopropyl‐diketone 2 und 3 umlagert. Neue Resultate vermitteln nun einen näheren Einblick in die mechanistischen Aspekte dieser Photoreaktion. Die Bestrahlung der 4α‐Trideuteromethyl‐Verbindung 7 in Dioxan mit 2537 Å lieferte nach einem Umsatz von ≧ 30% die an C‐4 sterisch äquilibrierten Photoisomerenpaare 8a, b und 9a, b während im regenerierten Ausgangsmaterial (7) die C(4)‐Chiralität erhalten blieb. Dieser Befund spricht gegen eine konzertierte Umlagerung und ist indikativ für einen schrittweisen Reaktionsablauf.

Haselbach, E.; Heilbronner, E.

doi: 10.1002/hlca.19700530403pmid: N/A

A correlation of the photoelectron spectra of trans‐2‐butene, trans‐acetaldehydemethylimin and trans‐azomethane shows that the split Δ = ε (ag(n))−ε (bu(n)) between the lone pair orbitals ag(n) and bu(n) of trans‐azomethane amounts to 3.3 ± 0.2 eV. Molecular orbital calculations by the MINDO/1 procedure indicate that ag(n) lies above bu(n). In agreement with the experimental results the π‐orbital au(π) is predicted to fall into the interval between ag(n) and bu(n).

Rothweiler, W.; Tamm, Ch.

doi: 10.1002/hlca.19700530404pmid: 5433434

From cultures of a Phoma species (strain S 298) (Fungi imperfecti) two new antibiotics, phomine (1) and 5‐dehydrophomine (4) have been isolated. Phomine and 5‐dehydrophomine represent a novel type of macrolide antibiotics, the large lactone ring being fused to a highly substituted octahydro‐isoindole system. Both show cytostatic activity.

Von Philipsborn, W.; Altman, J.; Babad, E.; Bloomfield, J. J.; Ginsburg, D.; Rubin, M. B.

doi: 10.1002/hlca.19700530405pmid: N/A

A prebullvalene lactone exhibits fluxional isomerism in solution. Analysis of proton NMR. spectra at 100 MHz and 220 MHz together with variable temperature studies show that the species existing in solution are 7, 8 and 9.

Bally, C.; Leuthardt, F.

doi: 10.1002/hlca.19700530406pmid: 5433435

The glyceraldehyde formed by oxidation of glycerol through alcohol dehydrogenase (E.C. 1.1.1.1) from horse liver has been condensed with phosphodihydroxyacetone using either rabbit muscle or liver aldolase. The single product was identified after silylation by gas chromatography as L‐sorbose‐1‐phosphate. No D‐fructose‐1‐phosphate was detected. Apparently liver alcohol dehydrogenase oxidizes glycerol stereospecifically to L‐(−)‐glyceraldehyde. Thus, the earlier conclusions of Hadorn et al. from chromatography of the borate complexes on Dowex 1 have been confirmed. The same stereospecific behavior was found for both isoenzymes III and IV. With Bis‐(trimethylsilyl)‐trifluoroacetamide L‐sorbose‐1‐phosphate and D‐fructose‐1‐phosphate are persilylated. Two trimethylsilyl groups are bound to the phosphate group. These bonds are not cleaved during gas chromatography.

Cocu, F. G.; Wolczunowicz, G.; Bors, L.; Posternak, Th.

doi: 10.1002/hlca.19700530407pmid: N/A

Cyclopentenones substituted in position 4, and 3, 5‐cis or ‐trans disubstituted cyclopentenes have been studied by NMR. and by IR. spectroscopy. Cyclopentenone derivatives and cyclopentene derivatives adopt a quasi‐coplanar and an envelope conformation, respectively. The preferential orientation of the substituents has been established according to their nature and to the solvents by correlation to the vicinal and the long‐range coupling constants.

Naranjo, J.; Hesse, M.; Schmid, H.

doi: 10.1002/hlca.19700530408pmid: N/A

The alkaloid lonicerine was isolated from Callichilia barteri (Apocynaceae). By chemical and spectroscopic evidence it could be shown to be 16‐epi‐aspidodasycarpine (1).

Felner, I.; Schenker, K.

doi: 10.1002/hlca.19700530409pmid: 5433436

The synthesis of the antibiotic anisomycin (1) is described. In the key step 3, 4‐dimethoxy‐thiopyrrolidone (16), prepared from diethyl L‐( + )‐tartarate (4) was converted to the thioiminoester 18, which upon treatment with trimethylphosphite yielded the benzylidene derivative 19. Cleavage of the ester group of 19 and hydrogenation of the decarboxylation product gave the two isomers 21 and 22. 22 was converted into desacetylanisomycin (3) and anisomycin (1).

Pecherer, B.; Stumpf, J.; Brossi, A.

doi: 10.1002/hlca.19700530410pmid: 5433437

In continuation of our study on new types of analgesics, we synthesized various hexahydro‐3‐benzazocines. The synthesis of these compounds, starting from well‐known intermediates, is described in this paper. The compounds do not exhibit biological activities worthy of further exploration.