Synthesis of new fundamental heterocycles. Part VII. Synthesis of 2-azaxanthene

2-Azaxanthone ( 5 ) has been conveniently prepared by condensation of the morpholine enamine of 1-benzyl-4-piperidone witli salicylaldehyde followed by chromium trioxide oxidation and subsequent aromatization. Lithium aluminum hydride reduction of 5 afforded the new fundamental heterocycle 2-azaxanlhene.     

Chemistry of thienopyridines. VII. Mechanistic studies on the synthesis of thieno[2,3-c] pyridine by thermolytic cyclization

A study was made of the formation of thieno[2,3-c]pyridine (1) from hydrogen sulfide and 4-vinylpyridine in a flow system at 630°. 2-(4-Pyridyl)ethanethiol and bis-2-(4-pyridyl)ethyl sulfide were found to be likely intermediates. Based on these studies, there was devised a two-step practical preparative method for I (optimum overall yield 58%) which consists of preliminary conversion of 4-vinylpyridine to benzyl 2-(4-pyridyl)ethyl sulfide and subsequent thermolysis (at 605°) of this substance.     

Vernetzung von Polyolefinen mit ultraviolettem Licht

Zusammenfassung Es wird gezeigt, daß sich neben verschiedenen Polyäthylen-Typen auch Äthylen-Propylen-Copolymerisate, Polypropylen und Polybuten-(1) durch ultraviolettes Licht vernetzen lassen, wenn man als Sensibilisatoren bestimmte Chlorkohlenwasserstoffe oder Dischwefeldichlorid verwendet. Die Festigkeit der vernetzten Produkte oberhalb ihres Schmelzpunktes wird mit dem ZST-Versuch gemessen. Die erreichten Reißzeiten unter Belastung sind z. T. recht hoch; die entsprechenden Vernetzungsgrade werden aus Bestimmungen des Gelanteils berechnet.     

Massenspektroskopische Fragmentierungsreaktionen. V—Zur Frage des Quasi–Thermischen RDA–Zerfalls

It is demonstrated with variously substituted steroids that it is not necessary to invoke quasithermal RDA decomposition to explain the fragmentation behaviour. The results suggest that such processes do not play an important role in mass spectrometric decomposition.     

Extraction of Nitric,Perchloric, and Hydrochloric Acid by N,N-dibutyl Diethyl Carbamyl Phosphonate

Extraction of nitric, perchloric, and hydrochloric acid by N,N-dibutyl diethyl carbamyl phosphonate in carbon tetrachloride was investigated. The data obtained are treated in terms of stepwise neutralization of the acid with the formation of species y · HA and y · 2HA in the organic phase, where y stands for the extractant and HA for the acid. The equilibrium constants, K?₁ and K?₂ for nitric acid were found to equal 0.24 ± 0.02 and 0.017 ± 0.005, respectively. In case of HClO₄ and HCl K?₁ were found to equal 0.031 ± 0.003 and 0.0039 ± 0.0005, respectively. A third phase was observed when extraction of HClO₄ was performed using acid concentration higher than 3.5 molar. The preference for partition of different acids was discussed on the light of the competition of the proton between the acid anion, water and the basic extractant as well as the degree of the ionization of different acids.     

The synthesis of diene and of vinyl copolymers containing predetermined quantities of polynuclear hydrocarbon or heterocyclic adducts—IV. Copolymers of butadiene or isoprene,anthracene and a linking agent

Evidence is given that, when solutions of diene monomers and anthracene in tetrahydrofuran are reacted with alkali metal and subsequently titrated with linking agents such as alkyl dihalides, copolymers are formed; they contain the 9,10-dihydroanthracene adduct and the diene in the same proportion as in the original solution. The structures of these copolymers have been elucidated by NMR spectroscopy and the mechanism of formation is discussed.     

Ovine luteinizing hormone. VI. Analysis of the misclassification errors in the separation of intrapituitary isohormones by chromatofocusing.

Luteinizing hormone (LH) in extracts of the ovine (o) anterior pituitary gland elutes as eight or more distinct peaks when analyzed by chromatofocusing on pH 10.5-7 gradients [Keel et al., Biol. Reprod., 36 (1987) 1102]. In order to examine the efficacy of this approach to identify the distinct charge isomers of oLH, a pool of pituitary extracts was de-salted by flow dialysis and chromatofocused on a pH 10.5-7 gradient. The immunoreactive oLH eluted in nine distinct peaks which were coded with letters beginning with the most basic form. The fractions corresponding to each peak were pooled, dialyzed and lyophilized. Each peak was then re-chromatofocused on a pH 10.5-7 gradient except for the immunoreactive oLH eluting in peak A' because of the small amount present in this peak. Each peak, except for F and H, also consisted of a small percentage of immunoreactive oLH associated with adjacent peaks. This was plausible because chromatofocusing does not generally yield baseline resolution of peaks. Peak H eluted in a broad manner and was contaminated with significant amounts of isohormones F, G and Z. In contrast, peaks B, E, F, G and Z almost completely eluted in the anticipated regions. Thus, it appears that analysis of oLH charge isomers by chromatofocusing yields minimal misclassification errors and that the misclassification errors observed are associated with molecular forms which comprise a relatively small percentage of the oLH in pituitary extracts.     

A photoplate calibration technique applied to the determination of hafnium in zirconium by SSMS

A photoplate calibration procedure is suggested for spark source mass spectrometry /SSMS/ with photoplate detection. The technique uses the Churchill two-line method applied to the two stable isotopes of copper. The calibration curve thus obtained is split into fragments and each fragment is approximated by a polynomial. The method was applied for the quantitative determination of Hf as impurity in zirconium sponge obtained from a pilot plant dedicated to the depletion of the hafnium content in zirconium by fractional crystallization.     

Koordinationsverbindungen von Aminoacridin-N-oxiden mit Metallthiocyanaten der 3d-Reihe

Coordination Compounds of Aminoacridine-N-oxides with Thiocyanates of the 3d Metals . Reactions of thiocyanates of the 3d metals with selected aminoacridine-N-oxides in homogeneous dilutions of N,N-dimethylformamide form compounds of the type [M(AAcNO)_a(DMF)_b(NCS)₂] · cDMF and [M′(AAcNO)_d(DMF)_e(NCS)₃] · fDMF, M = Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺; M′ = Cr³⁺, Fe³⁺; AAc^INO = 3,6-diamino-2,7-dimethylacridin-N-oxide, AAc^IINO = 3,6-bis(dimethylamino)acridin-N-oxide, AAc^IIINO = 2-ethoxy-6,9-diaminoacridin-N-oxide; a = 1, 2, 3, 4; b = 0, 1; c = 0, 1, 2, 3; d = 1, 2, 3; e = 0, 1, 2; f = 0, 1, 2, 3. The complexes are characterized by IR (4000–200 cm^?1) and UV-VIS spectra in solutions and solids and by EPR and conductivity investigations.