1,2-Dipyridazinyl-äthen- und-äthan-1,2-diole aus Pyridazin-carbaldehyden

Treatment of pyridazine-4-carboxaldehyde with catalytic amounts of KCN results in formation of pyridazine-4-carboxylic acid and two stereoisomeric diols (4,5). The configurations of4 and5 are explained on basis of the¹H-NMR-spectra, the mechanism of reaction is discussed. Pyridazine-3-carboxaldehyde (10) reacts with HCN to form the addition product of10-cyanhydrine to10 (11). HCN-elimination from11 yields the enediol12 which by oxygen is oxidized to pyridazine-3-carboxylic acid or its methyl ester.

---

---

Herrn Univ.-Prof. Dr.M. Pailer mit den besten Wünschen zum 65. Geburtstag gewidmet.

---

5. Mitt.:G. Heinisch, E. Luszczak undM. Pailer, Mh. Chem.105, 763 (1974).     

1,2-Dipyridazinyl-?then- und-?than-1,2-diole aus Pyridazin-carbaldehyden

Treatment of pyridazine-4-carboxaldehyde with catalytic amounts of KCN results in formation of pyridazine-4-carboxylic acid and two stereoisomeric diols (4,5). The configurations of4 and5 are explained on basis of the¹H-NMR-spectra, the mechanism of reaction is discussed. Pyridazine-3-carboxaldehyde (10) reacts with HCN to form the addition product of10-cyanhydrine to10 (11). HCN-elimination from11 yields the enediol12 which by oxygen is oxidized to pyridazine-3-carboxylic acid or its methyl ester.     

1,2-Epoxycarotinoide. 3. Mitteilung. Isolierun von 1,2-Epoxy-1,2-dihydrolycopin aus Tomaten

1,2-Epoxycarotenoids: Isolation of 1,2-Epoxy-1,2-dihydrolycopene from Tomatoes The optically active, 1,2-epoxy-1,2-dihydrolycopene was isolated from tomatoes. Its constitution was established by comparison with the racemic synthetic compound.     

Eucalyptol aus Eukalyptusöl

Eucalyptol (1,8‐cineol), a cyclic monoterpenoid ether, is the dominant portion of eucalyptus oil, an essential oil of Eucalyptus globulus, accessible by steam distillation of its leaves. Some herbs and spices such as basil and cardamom also contain it as characterising flavour compound. Eucalyptus is a very diverse genus of Myrtaceae naturally occurring in Australia to whom the species have adapted in evolution. Planting Eucalyptus trees outside Australia has both benefits for poor populations and drawbacks. Especially, the enormous water consumption has been criticized. The total impact is doubtful. Eucalyptol is used in flavorings, fragrances, confectionery, cosmetics, cough suppressants, and insect repellents. Higher than normal doses are a hazard. A convenient isolation of eucalyptol from eucalyptus is reported. All analytical spectra were recorded and are reproduced and interpreted either in the main part or in the supporting information. The project is a follow up of the recent book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009).     

Polymere aus 6-Acryloylamino-2,3diphenylchinoxalin

Ohne Zusammenfassung     

Anilinochinone und Chinonanile aus 4,4′-Bi-(1,2-naphthochinon)

4,4-Bi-(1,2-naphthoquinone) (1) reacts with several aromatic amines to yield the anilino-quinones2 a-k. Compound2 a is characterized by the binaphthoquinone dioxime6 and the semicarbazide8. The reductive benzoylation of2 a gives the benzoylester5. The aminoquinones2 a-g can be oxidized yielding the quinone-aniles3 a-g. IR and MS spectra of2 and3 are discussed.

     

Improved synthesis of 6-deoxy-1,2-O-isopropylidene-β-L-talofuranose and 6-deoxy-1,2-O-isopropylidene-β-L-idofuranose

Summary The key step in the preparation of 6-deoxy-1,2-O-isopropylidene--L-talofuranose (7) and 6-deoxy-1,2-O-isopropylidene--L-idofuranose (13) is the selective exchange of the 6-O-mesyl rest of 3-O-acetyl-5,6-O-dimesyl-1,2-O-isopropylidene--D-allofuranose (4) and 3-O-acetyl-5,6-O-dimesyl-1,2-O-isopropylidene--D-glucofuranose (10) by acetate group (potassium acetate/18-crown-6).

---

Ein neuartiger und präparativ nützlicher Zugang zu 6-Desoxy-1,2-O-isopropyliden--L-talofuranose und 6-Desoxy-1,2-O-isopropyliden--L-idofuranose

Zusammenfassung Schlüsselschritt bei der Herstellung von 6-Desoxy-1,2-O-isopropyliden--L-talofuranose (7) und 6-Desoxy-1,2-O-isopropyliden--L-idofuranose (13) ist der selektive Austausch der primären Mesyl-Gruppe in 3-O-Acetyl-5,6-O-dimesyl-1,2-O-isopropyliden--D-allofuranose (4) und 3-O-Acetyl-5,6-O-dimesyl-1,2-O-isopropyliden--D-glucofuranose (10) durch den Acetat-Rest in Gegenwart von Kaliumacetat/Kronen-Ether.