No abstract

The near ultraviolet spectra of the diazines and various derivatives have been obtained in several solvents. Intensities, contours, and positions of the observed bands are combined with a valence-bond treatment of the diazine π-electrons to assign the transitions and to evaluate the C–C and C–N exchange integrals. The diazine band near 30,000 cm−1 (3333A) is assigned to a nonbonding nitrogen electron transition, and the band near 40,000 cm−1 (2500A) to a π-electron transition.

No abstract

Apparent pK-values have been determined for 56 aromatic acids in the solvent system methylcellosolve (80 wt.-%)/water (20 wt.-yo) with a previously described fully automatic titration apparatus. The validity of the Hamrnett equation waE tested and found to express the experimental data with a deviation comparable with data for aqueous systems. Reaction constants e are given for the apparent pK-values of phenols, benzoic acids, salicylic acids and benzenesulfonanilides in the solvent system mentioned. The additivity of the effects of aromatic suhstituents on the apparent pK-values was tested and found to be comparable with the data for pK-values measured in aqueous media.

Aus der Wurzelrinde von Aspidosperma ulei Mgf. wurde in ca. 0,6‐proz. Ausbeute ein bisher nicht beschriebenes Dihydro‐carbazol‐Alkaloid, Ulein genannt, isoliert, für welches auf Grund von Abbauresultaten verschiedene Strukturen diskutiert werden.