Novel heterocycles. 3. Synthesis of fused 1,3,2-benzodiazaphosphorin ring systems

Novel fused tricyclic phosphorus heterocycles 9 and 11 and the tetracycle 15 were synthesized by cyclization of 1-haloalkyl (or 3-haloalkyl)-2,3-dihydro-1,3,2-benzodiazaphosphorin-4(1H)one 2-oxides with sodium hydride. Some spectral data of the products are also discussed.     

IR laser-induced dehydrohalogenation of halogenated ethanes

Pulsed IR radiation from a CO₂ TEA laser has been shown to cause dehydrohalogenation of CF₃CH₃, CF₂ClCH₃ and C₂H₅Cl under collisionless conditions. IR emission has been observed and is attributed to HF² and CF₂CH₂² from CF₃CH₃, and to HF² and HCl² from CF₂ClCH₃.     

Chemistry of the phenoxathiins IV. Synthesis of 9-substituted 1 -azaphenoxathiins

In an extension of recently reported syntheses of the I-azaphenoxathiin nucleus as well as several 7-substituted analogs, the synthesis of several 9-substituted members of this series is now reported. In addition, the first ¹³C-nmr spectral evidence of an interaction between a sulfur atom and the oxygen of an ortho-nilro group which has been previously observed only in X-ray erystallographic studies is also described. The possible consequences of this interaction on the reaction pathway leading to the cyclization of the 9-substituted J-azaphenoxathiin nucleus is also presented.     

A modification of the heteropoly blue method for the microgram determination of arsenic in biological materials

Summary A sensitive method has been developed for analysis of trace amounts of arsenic in biological materials using the heteropoly blue method. The method employs a closed apparatus and a nitrogen atmosphere, and allows the detection of arsenic in ppm concentration using samples of 100 mg.

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Zusammenfassung Eine empfindliche Methode zur Bestimmung von Arsenspuren in biologischem Material im Wege der Molybdänblaumethode wurde ausgearbeitet. Man arbeitet dabei in einer geschlossenen Apparatur in Stickstoffatmosphäre und kann so in 100-mg-Proben Arsenkonzentrationen in der Größenordnung von ppm bestimmen.

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Presented at the 6th Annual Northeast Regional Meeting of the American Chemical Society, Burlington, Vermont, August 19, 1974.     

Bioluminescent reporter bacteria detect contaminants in soil samples

Applied Biochemistry and Biotechnology - Reporter strains of bacteria were tested using soil samples from several sites near a leaking fuel oil storage facility. The reporter bacteria utilized the...     

Regioselective synthesis of pyrido[2,3-d]pyrimidines

The reaction of diethyl ethoxymethylenemalonate ( 1 ) and 6-amino-1,3-dimethyluracil ( 2 ) was determined to be regioselective. Under acidic conditions the product was the previously isolated 7-oxopyrido[2,3-d]pyrimidine ( 3 ), while in the presence of one equivalent of base followed by thermal cyclization, the isomeric 5-oxopyrido[2,3-d]pyrimidine ( 5 ) is formed.     

Synthesis of reduced complex oxides of molybdenum by fused salt electrolysis

Fused salt electrolysis has been used to prepare a number of reduced oxides of molybdenum with lanthanum, neodymium, and yttrium in single crystal or oriented polycrystalline form. The average valence of molybdenum in the various compounds ranged from 5.67 to 3.50. Previously unreported compounds include La₅Mo₄O₁₆ (triclinica = 5.64 Å,b = 20.7 0Å,c = 5.64 Å, α = 86.55°, β = 90.0°, γ = 93.45°); La₂Mo₂O₇ (orthorhombic,a = 12.19 Å,b = 6.05 Å,c = 3.87 Å); LaMo₂O₅ (hexagonal,a = 8.378 Å,c = 19.26 Å). In addition, single crystal specimens have been prepared of Y₂MoO₅,Ln₅Mo₃O₁₆(Ln =La, Nd) and metal atom cluster compounds of theA₂Mo₃O₈ type (A = Mg, Co, Ni, Zn).     

Capillary electrophoresis separation of heterocyclic nitrosoamino acid-conformers at sub-ambient temperatures

The separation of a selected group of naturally occurring, heterocyclic nitrosoamino acids was achieved by capillary zone electrophoresis and the resolution of the syn and anti conformers improved as the temperature was lowered to 5 °C. The double peaks observed for each nitrosoamino acid are probably caused by the slow kinetics of conformational isomerism. The experimental setup consisted of a P/ACE 5510 electrophoresis system, a 57 cm polyacrylamidecoated capillary, and a 10 mM phosphate buffer, pH 7.2, containing 2 mM of 3-(N-N-dimethylmyristylammonio)propanesulfonate (DMMAPS) and 0.1% Tween 20. Our study shows that (a) the lower the temperature, the greater the resolution and the longer the migration times; and (b) different nitrosoamino acid conformers were resolved at different temperatures because of differences in the rate of isomerization. For example, the conformers of N-nitrosothiazolidine-4-carboxylic acid were partially resolved at 30 °C while those of N-nitrosoproline were well resolved at the same temperature.     

ESR STUDY OF ORIENTED TRIPLET MOLECULES GENERATED BY EXCITATION WITH POLARIZED LIGHT

Abstract— The lowest-lying triplet states of a variety of aromatic molecules and complexes have been generated by the irradiation of these compounds in solvent glasses with plane-polarized light. Measurements of the allowed (Δ M=± 1) ESR transitions clearly demonstrate that the triplets so formed are oriented with respect to the external magnetic field. By this method the triplet zero-field splitting parameters, D and E , can be evaluated simply and reliably. Intramolecular energy transfer is postulated to explain the triplet spectra of Zn( o -phen)₂(NO₃)₂ and Zn( o -phen)₃(NO₃)₂. It was observed that in triplet-triplet energy transfer from benzophenone to naphthalene there is no apparent orientation requirement between the donor and acceptor molecules. Further areas of significance and application of this technique are suggested.