InCl3-mediated addition of indole to isatogens: an expeditious synthesis of 13-deoxy-isatisine A

A strategy directed towards the total synthesis of isatisine?A that involves several late-stage metal-catalyzed transformations that address the key carbon-carbon and carbon-heteroatom bond formations has been developed. As a part of this strategy, methods for the addition of indoles to isatogens that lead selectively to either 2,2-disubstituted N-hydroxyindolin-3-one or 2,2-disubstituted indolin-3-one compounds have been developed by employing InCl(3) as a catalyst or as the reagent. The present methods provide the first examples of the additions of indoles to the isatogen nucleus. To demonstrate its viability, the synthesis of 13-deoxy-isatisine?A has been completed in ten steps from a known and easily available lactone.     

Synthesis of 1,2,3‐Triazole Substituted Isoxazoles via Copper (I) Catalyzed Cycloaddition

The synthesis of a series of 3,5‐disubstituted isoxazole‐4‐carboxylic esters containing N‐substituted 1,2,3‐triazoles ( V ) starting from various benzaldehydes ( I ) is reported. Benzaldehydes undergo oximation with hydroxylamine hydrosulfate. Later, chlorination followed by condensation with methylacetoacetate and the hydrolysis of the resulting ester afforded respective carboxylic acid ( II ), which on chlorination with PCl₅ gave the corresponding acid chlorides ( III ). The coraboxylic acid chlorides ( III ) on propargylation gave propargylic esters ( IV ) and these on click reaction gave the title compounds ( V ).     

Depth profiling of oxygen in oxide films by 18O(p,α)15N nuclear reaction analysis

The paper describes the determination and depth profiling of oxygen in thin oxide films using ¹⁸O(p,??)¹⁵N nuclear reaction. The excitation function of ¹⁸O(p,??)¹⁵N nuclear reaction exhibits a resonance at 629?keV and a plateau at 730?keV with uniform cross-section. The resonance is used to determine the depth profile of oxygen in films while the plateau, to estimate its overall concentration. The resonance, characterized by a width of 2.1?keV enables high-depth resolution (~20?nm) measurements and has a probing depth of more than a micron. The paper presents depth profile measurements of oxygen in several metal oxide films (SiO₂, TiO₂ and HfO₂) using this resonance. Possible interferences arising from ¹⁵N(p,??)¹²C, ¹⁹F(p,??)¹⁶O and ¹¹B(p,??)2?? nuclear reactions are also discussed. It has been shown that it can serve as a suitable alternative to 3.05?MeV ¹⁶O(??,??)¹⁶O resonant scattering which is generally used for depth profiling oxygen. It is, in fact, more reliable and precise in materials that witness significant large angle multiple scattering. It can also be advantageously used to monitor ¹⁸O, when used as a tracer.     

Incoherent scattering functions of 145 keV gamma rays by K-shell electrons in Y,Ag and Au

The values of incoherent scattering functions are determined experimentally for 145 keV gamma rays in elements Au, Ag and Y at scattering angles 40°, 70° and 100°, using a x-ray gamma coincidence technique. The corresponding theoretical values are obtained from the tabulations of Hubbellet al, and computed from the models of Jauch and Rohrlich and Shimizuet al. A comparison between the theoretical and experimental results showed that the non-relativistic approach adopted in the theory of Shimizuet al is inapplicable to the present cases. A gross agreement is noticed between the present experimental results and the other theoretical values.     

Some studies on thallium oxalates

Two methods (the Horowitz-Metzger and the Dharwadkar-Karkhanavala) for calculating the apparent activation energies of different thallium(I) oxalates were compared. The Dharwadkar-Karkhanavala method gave consistent values.     

Electron impact induced cyclizations in 4-chioro-3-(N-aryliminomethyl) (2H) benzopyrans and benzothiopyrans

Intramolecular substitutions leading to cyclizations with the ejection of chlorine have been noticed during mass spectral fragmentation of 4-chloro-3-(N-aryliminomethyl) (2H) benzopyrans and benzothiopyrans. Very interesting ortho effects involving intramolecular substitutions have also been observed in 6-methyl-4-diloro-3-[N-(2-methoxyphenyliminomethyl)] (2H) benzopyran and 6-methyl-4-chloro-3-[N-(2-chlorophenyliminomethyl)]-(2H) benzopyran. The proposed fragmentation mechanisms have been supported by the accurate mass measurements and linked scan studies.     

Ortho effects in organic molecules on electron impact part 22. Competing oxygen transfers from the nitro group to sulphur and the olefinic double bond in 2-nitrophenyl styryl sulphides

Double oxygen migration to sulphur from the ortho-nitro group leading to eliminations of SO₂ and ^·SO₂H from the molecular ions and single oxygen transfer to the olefinic double bond in the side-chain giving rise to the most abundant ion at m/z 138 have been observed in 2-nitrophenyl styryl sulphides on electron impact. The proposed fragmentation mechanisms and the product ion structures were confirmed with the aid of high-resolution data, B/E linked scan and CID spectra.     

Some studies on thallium oxalates. XIII. Sodium bis-oxalatodiaquothallate(III) monohydrate

Sodium bis-oxalatodiaquothallate(III) monohydrate has been prepared and characterised by chemical, thermal, X-ray diffraction and infrared spectroscopic methods. Thermoanalytical studies indicated that the complex decomposes through the formation of a mixture of thallium(I) oxalate and sodium oxalate, the final product at 650° being a mixture of thallium(I) oxide, thallium(III) oxide and sodium carbonate.

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Zusammenfassung Natrium-bis-oxalatodiaquothallat(III)-Monohydrat wurde hergestellt und chemisch, thermoanalytisch, röntgendiffraktometrisch und infrarotspektroskopisch charakterisiert. Thermoanalytische Untersuchungen haben ergeben, daß sich der Komplex unter Bildung eines Gemisches von Thallium(I)- und Natriumoxalat als Zwischenprodukt zersetzt. Endprodukt der Zersetzung bei 650° ist ein Gemisch von Thallium(I)-oxid, Thallium(III)-oxid und Natriumcarbonat.

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, --- () . , . 650° - .

     

Determination of the stoichiometry of vanadium nitride films by proton back-scattering

Vanadium nitride films were grown on stainless steel and silicon, with different nitrogen concentrations by varying the partial pressures of nitrogen in a DC magnetron sputtering set up. These films were characterized for their composition by proton back-scattering and their micro hardness values were correlated with their N/V ratio.     

Ortho effects in organic molecules on electron-impact I—Oxidation of olefinic double bond by the ortho nitro group in stilbazoles

The electron-impact-induced fragmentation in 2′-nitro-4-stilbazole is triggered by the oxidation of the olefinic double bond by the ortho nitro group in the initial step, while such an interaction under the same condition is totally absent in the meta and para isomers. The important fragmentation in 2′-nitro-2-stilbazole is the formation of a cyclised ion with the elimination of the nitro group.