Darstellung und Umwandlungen von 4-Anilino-1,2-dihydro-7,8-benzochinazolon-(2)

Zusammenfassung Bei der Kondensation von Phenylsenföl mit N-Phenyl-N-(naphthyl-[1])-guanidin entsteht 2,4-Dianilino-7,8-benzochinazolin (I), welches bei der alkalischen Hydrolyse bei 180° nicht überschreitenden Temperaturen in 4-Anilino-1,2-dihydro-7,8-benzochinazolon-(2) (III) übergeht.

---

Condensation of phenyl isothiocyanate with N-phenyl-N-(naphthyl-[1])-guanidine gives 2,4-dianilino-7,8-benzoquinazoline (I), which on alkaline hydrolysis at temperatures not over 180° yields 4-anilino-1,2-dihydro-7,8-benzoquinazolone-(2) (III).

     

Synthese und Umwandlungen von Isoxazolidin-Nucleosiden

Synthesis and Transformations of Isoxazolidine-Nucleosides Reaction of the oxime 12 with formaldehyde, acetaldehyde or acetone in the presence of methacrylic acid methylester leads in a highly stereoselective 1,3 dipolar cycloaddition of the corresponding nitrones to the protected isoxazolidine ribosides 13, 14, 20, 21 and 26 (Scheme 1 and 2). Using a new, mild procedure to effect detriylation, the cycloaddition products were transformed into the alcohols 16–19 , 22–25 and 27 . Cleavage of a mixture of the glycosides 16 and 17 yielded the N-unsubstituted isoxazolidine 29 in 65% optical purity while the cleavage of 27 gave optically pure 28 . Alternatively, the isoxazolidine ribosides 13, 14, 16–18 and 26 were transformed via reductive cleavage of the isoxazolidine N-O bond and subsequent lactamization into the corresponding pyrrolidinone-ribosides 30, 33, 35, 42, 49 and 50 , the ribitolyl pyrrolidinones 31, 34, 36–39 and 43–46 (see Scheme 4) and the ribitolyl isoxazolidine 47 .     

Mechanochemische Umwandlungen und Synthesen von Polymeren

Ohne Zusammenfassung     

Die Umwandlungen von lebenden α-Methylstyrol-Tetrameren

Ohne Zusammenfassung     

Die gaschromatographische Bestimmung von cis- und trans-Cyclohexandiol-(1,2) in Kunstharzen

Ohne Zusammenfassung