Synthese von 3-Nitro-1,1-bis(triisopropylsilyl)-1H-cyclopropabenzol und Azocyclopropabenzol-Derivaten

Synthesis of 3-Nitro-1,1-bis(triisopropylsilyl)-1H-cyclopropabenzene and Derivatives of Azocyclopropabenzene 1,1-Bis(triisopropylsilyl)-1H-cyclopropabenzene ( 4 ) can be nitrated at C(3) without opening of the three-membered ring. Further functionalized cyclopropabenzenes are available in this way.     

Synthese von 2-Thia-6-aza-adamantan und Derivaten

The synthesis of 2-thia-6-aza-adamantane ( 19 ) and several of its derivatives was achieved starting from 9-azabicyclo[3.3.1]nona-2,6-diene ( 9 ) which was prepared from cis, cis-cycloocta-1, 5-diene ( 1 ). Transannular addition of sulfur dichloride to its N-benzenesulfonyl and N-formyl derivatives 10 and 11 yielded the tricyclic dichlorides 12 and 13 , respectively; the 2-thia-6-aza-adamantanes 14–19 were synthesized from 13 .     

Synthese und Eigenschaften von [n] (2,5) Pyridinophanen und ihren Derivaten

[n] (2,5) Pyridinophanes (I) have been synthesized by acid catalyzed cyclization of bis-(β-aminovinyl)-diketones to [n] (2,5) pyridinophan-n-ones (V), followed by WOLFF -KISHNER reduction. The conformational stability of the lower members (n < 12) of the series is shown by reduction of V to diastereomeric [n] (2,5) pyridinophan-n-ols (XI). In addition [9] (2,5) pyridinophane (I, n = 9) has been resolved into enantiomers.     

Synthese und Struktur von assoziiertem μ-Phosphinodiboran und von phosphorsubstituierten Derivaten

Associated -phosphinodiborane, (-H₂PB₂H₅) _n , is formed in the reaction of H₂P(BH₃)₂Na with HCl in diethyl ether solution at –96°C. The formation of B–H–B bridges is demonstrated by IR and¹¹B-NMR spectra. (-H₂PB₂H₅) _n decomposes thermally to diborane and polymeric phosphinoborane analogous to -H₂NB₂H₅. Other phosphorus substituted -phosphinodiboranes associated via B–H–B bridges are formed in the reaction of the salts (CH₃)PH(BH₃)₂Li, (CH₃)₂P(BH₃)₂Li, andPhPH(BH₃)₂Li with HCl.

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Mit 6 Abbildungen

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Herrn Professor Dr.E. Hayek zum 70. Geburtstag gewidmet.     

Synthese und Umlagerungsreaktionen von 2-(2-Amino-anilino)-2-imidazolin-Derivaten

The nitro-imidazolines V and VI are formed by addition reaction of ethylenediamine to the isothiocyanates III and IV. The nitro group is then converted by hydrogenation to the amino group, giving XI and XII, which can be acylated selectively to IX and X. By rearrangement in boiling xylene, the compounds XI and XII give the corresponding 2-(2-aminoethylamino)-benzimidazoles XIII and XIV. The benzoylated derivative IX gives the benzimidazole derivative XVIII by rearrangement and subsequent migration of the benzoyl group, while the benzylated derivative XVI gives the rearranged benzimidazole XXII. The benzimidazole structure of the rearranged products is proven by unambiguous synthesis of XIII, starting with 2-chlorobenzimidazole (VII) and mono-N-acetyl-ethylene-diamine to give compound VIII, from which XIII is obtained by hydrolysis.     

Synthese von 2- und 3-(1,2,3,6-Tetrahydropyridyl)-indolen

The synthesis of a series of 2- and 3-(1,2,3,6-tetrahydro-4-pyridyl)-indoles by reduction of the corresponding pyridinium compounds with sodium borohydride is described. A substantially improved mode of preparation for 3-(4-pyridyl)-indole is given.     

Bestimmung von Nitrofurazon (5-Nitro-2-furaldehydsemicarbazon)

Ohne Zusammenfassung     

Synthese von 4-Benzylthio- und 4-(Arylthio)-1,3-oxazol-5(2H)-onen

Synthesis of 4-(Benzylthio)-and 4-(Arylthio)-1,3-oxazole-5(2H)-ones Following a known procedure, 4-(benzylthio)-1,3-oxazol-5(2H)-one ( 4a ) was synthesized starting from sodium cyanodithioformate ( 1 ) and cyclohexanone (Scheme 1). The structure of the intermediate 4-(benzylthio)-1,3-thiazol-5(2H)-one ( 3a ) was established by X-ray crystallography. An alternative route was developed for the synthesis of 4-(arylthio)-1,3-oxazol-5(2H)-ones which are not accessible by the former reaction. Treatment of ethyl cyanoformate ( 5 ) with a thiophenol in the presence of catalytic amounts of Et₂NH and TiCl₄, followed by addition of a ketone and BF₃.Et₂O in a one-pot-reaction, gave 4f–i in low-to-fair yields (Scheme 3). Both synthetic pathways-complementary as for benzyl–S and aryl-S derivatives–seem to be limited with respect to variation of substituents of the ketone.     

Die Oxidation von 3-(1-Nitro-2-oxocycloalkyl)propanal

The Oxidation of 3-(1-Nitro-2-oxocycloalkyl)propanal Oxidation of the title compound 1 with KMnO₄ under neutral conditions led to the corresponding acid 2 , 5-(2,3,4,5-tetrahydro-2-nitro-5-oxo-2-furyl)pentanoic acid ( 4 ), and 4-oxononadioic acid ( 6 ). On the basis of experimental results the mechanism of the formation of 4 is discussed (Scheme 1). Oxidation of 1 with KMnO₄ under basic conditions gave 6 which was transformed to (E)-4,5-dihydro-5(2′-oxocyclopentyliden)furan-2(3H)-one ( 12 ) with benzene/TsOH (Scheme 3). In contrast to this result the corresponding 4-oxoheptandioic acid ( 22 ) yields 1,6-dioxaspiro[4,4]nonan-2,7-dione ( 23 ) only (Scheme 4).     

Eine Methode zur Bestimmung von N-(5-Nitro-2-furfuryliden)-1-aminohydantoin (Nitrofurantoin) im Harn

Ohne Zusammenfassung