Preparation,structure and asymmetric diels-alder reactions of 10-arylsulfonylisobornyl acrylates

The crystalline chiral auxiliaries 4 and 5 were readily prepared from camphorsulfonic acid. Their acrylates underwent the diels-alder reactions 6 → 7 with modest asymmetric induction consistent with an X-ray study of $\text{6a}$.     

Eine chromatographische Adsorptionsmethode zur quantitativen Bestimmung und Trennung von Oestron, Oestradiol und Oestriol im Urin

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Eine spezifische Reaktion auf Formaldehyd

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Die Analyse bin?rer Gemische, bestehend aus einem aromatischen Kohlenwasserstoff und einem Kohlenwasserstoff der Paraffin- oder Naphthenreihe

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1H, 13C and 15N NMR assignments of phenazopyridine derivatives

Phenazopyridine hydrochloride (1), a drug in clinical use for many decades, and some derivatives were studied by one- and two-dimensional (1)H, (13)C and (15)N NMR methodology. The assignments, combined with DFT calculations, reveal that the preferred protonation site of the drug is the pyridine ring nitrogen atom. The chemoselective acetylation of phenazopyridine (2) and its influence on the polarization of the azo nitrogen atoms were evidenced by the (15)N NMR spectra. Molecular calculations of the phenazopyridines 2-4 show that the pyridine and phenyl groups are oriented in an antiperiplanar conformation with intramolecular hydrogen bonding between the N-b atom and the C-2 amino group preserving the E-azo stereochemistry.     

Ein acidimetrisches Bestimmungsverfahren alkylsubstituierter 1-Methyl-4-piperidone

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