High-performance liquid chromatographic determination of D-amino acid oxidase activity.

A new procedure for the assay of D-amino acid oxidase activity has been developed. alpha-Ketoisovaleric acid, derived from D-valine, was estimated by high-performance liquid chromatography after reaction with o-phenylenediamine to give the corresponding quinoxalinol derivative. alpha-Ketovaleric acid was used as an internal standard to ensure the reproducibility of the method. As an example of application, kidney cortex homogenates were analyzed for their D-amino acid oxidase activity. The advantages of the presented procedure for the determination of the enzymatic activity in biological samples compared with previously reported procedures are discussed.     

Determination of the purity,melting point and heat of melting of cyclic polyethers

Conclusions Differential scanning calorimeter was used to determine the thermal stability, purity, melting point, and heat of melting of benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-24-crown-8. These crown ethers have relatively high heats of melting.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 691–692, March, 1986.     

Structure of surface compounds formed during chemisorption of BBr3 on dehydrated Aerosil

The chemisorption of boron bromide on the surface of Aerosil calcined at 870 K in vacuo was studied by IR spectroscopy combined with chemical and gravimetric analysis. It was determined that the chemical reaction of structural silanol groups with BBr₃ vapor occurs monofunctionally with the formation of SiOBBr₂ groups. This indicates uniform distribution of isolated silanol groups on the surface of dehydrated Aerosils.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 3, pp. 374–377, May–June, 1989.     

Diethyl benzoylphosphonate as a ligand

Summary Complexes (2 : 1) of diethyl benzoylphosphonate (debp) with 3d metal perchlorates were synthesized and characterized by means of i.r. and electronic spectral, magnetic susceptibility and conductance measurements. In new complexes of the types [M(debp)₂(OClO₃)(OH₂)](ClO₄) (M = Fe, Co, Zn) and [Fe(debp)₂(OClO₃)(OH₂)](ClO₄)₂, both debp ligands function as bidentate chelating agents, coordinating through the P=O and C=O oxygens. In contrast, in the manganese(II) and nickel(II) complexes, which are of the [M(debp)₂(OClO₃)(OH₂)₂](ClO₄) type, one debp acts as a bidentate chelating ligand, while the second debp is unidentate, coordinating only through the P=O oxygen. Hexacoordination in the new cationic complexes is completed by coordination of aqua and unidentate perchlorato ligands, which are in competition for sites in the inner coordination sphere of the central metal ion with the weak debp ligand. On the other hand, debp, owing to its bulkiness, and especially the presence of the benzoyl substituent, introduces sufficiently severe steric hindrance during coordination. As a result of this, the formation of [M(debp)₃]ⁿ⁺ tris-chelate cationic complexes with the 3 d metal ions under study does not seem to be possible.     

The dependence of the fatty-acid composition of cottonseed oil on the degree of unsaturation

Summary 1. Results of thiocyanometric and spectrophotometric analysis of cottonseed oil confirm the relationship found previously in catalytic hydrogenation using potentiometric monitoring of the state of the catalyst.2. Together with Eqs. (3) and (4), these results counterbalance the results of the chromatographic analysis of cottonseed oil.3. This contradiction leads to the posing of the question of the probable inaccuracy of individual methods of chromatographic analysis for substances with similar absorption properties, i.e., for linoleic and oleic acids.Alma-Ata Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 697–700, November–December, 1975.     

Magnetic behavior of copper diethyldithiocarbamate at low temperatures: A reinvestigation

The title compound, Cu(S₂CNEt₂)₂, behaves at low temperatures (1–20 K) as a normal spin-1/2 molecule, with 〈g〉 =2.06 and the Curie-Weiss θ = +0.25 K. This result contradicts an earlier investigation that led to the suggestion that the crystallographically-occurring dimers are coupled ferromagnetically.     

Diene synthesis with 2-pyrones and 2-pyridones XIV. 1,4-Cycloadducts of 1-alkyl-2-pyridones with N-phenylmaleinimide and maleinimide

1-Alkyl-2-pyridones react with N-phenylmaleinimide and maleinimide stereoselectively via the scheme of the diene synthesis to give imides of 8-alkyl-8-azabicyclo[2.2.2]-4-octen-7-one-1,2-dioic acid. 3-Unsubstituted 2-pyridones form adducts with an endo configuration, whereas 1,3-dimethyl-2-pyridone gives an exo adduct under the same conditions. The endo- and exo-bridge adducts readily undergo retrograde diene disintegration on heating.     

Nachweis von Peroxiden,Hydroperoxiden und Persäuren

Zusammenfassung Die Indikatorbase 4-Methoxyphenylazo--naphthylamin wird von p-Nitrobenzoylperoxid in neutralem oder saurem Medium ohne, von p-Nitrobenzopersäure unter Erwärmen oxydiert, gar nicht aber von p-Nitroäthylbenzol--hydroperoxid. Auf der Grundlage dieses Verhaltens können die drei Verbindungen unterschieden und p-Nitrobenzoylperoxid nachgewiesen werden. Die Indikatorsäure 4-Nitrophenylazo-2-amino-5-nitrobenzol wird von p-Nitroäthylbenzol--hydroperoxid oxydiert, nicht aber von p-Nitrobenzoylperoxid und p-Nitrobenzopersäure. Mit dieser Farbreaktion kann p-Nitroäthylbenzol--hydroperoxid nachgewiesen werden. p-Nitrobenzopersäure kann neben p-Nitroäthylbenzolhydroperoxid mit einer Farbreaktion von p- + m-Phenylendiamin nachgewiesen werden. Auch p-Nitrobenzoylperoxid gibt die Reaktion, aber p-Nitroäthylbenzol--hydroperoxid setzt sich nicht um.

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Detection of peroxides, hydroperoxides, and peracids

Summary The indicator base 4-methoxyphenylazo--naphthylamine is oxidized in neutral medium without warming byp-nitrobenzoyl peroxide, and byp-nitrobenzoperacid with warming, but it is not oxidized at all byp-nitroethylbenzene--hydroperoxide. The three compounds may be differentiated on the basis of these behaviors and furthermore it is thus possible to detect and identifyp-nitrobenzoyl peroxide. The indicator acid 4-nitrophenylazo-2-amino-5-nitrobenzene is oxidized byp-nitroethylbenzene--hydroperoxide but not byp-nitrobenzoyl peroxide andp-nitrobenzoperacid.p-Nitroethylbenzene--hydroperoxide may be detected through this color reaction.p-Nitrobenzoperacid can be detected in the presence ofp-nitroethylbenzene--hydroperoxide by a color reaction withp + m-phenylenediamine but no reaction is given byp-nitroethylbenzene--hydroperoxide.

     

Untersuchungen über die Oxydation von Butylbenzol in flüssiger Phase in Gegenwart von Kobalt- und Mangansalzen der Pyridincarbonsäuren

Zusammenfassung Es wurde der Einfluß der Kobalt- und Mangansalze der -, - und -Pyridincarbonsäuren auf die Luftoxydation von Rutylbenzol in flüssiger Phase untersucht. Dabei wurde festgestellt, daß das Kobaltpicolinat, Manganisonicotinat und Kobaltisonicotinat den Oxydationsverlauf zur Bildung von Carbonylverbindungen und Säuren lenken. Das Manganpicolinat weist ein selektives Oxydationsvermögen auf, vorwiegend zur Bildung von Estern.

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Liquid phase oxidation of butyl-benzene in presence of Co and Mn pyridine carboxylates

The influence of Co- and Mn-salts of -, - and -pyridinecarboxylic acids, resp., on the oxidation of butylbenzene by air has been studied. It has been found that the Co salt of picolinic acid, Mn and Co isonicotinate direct the oxidation process in favour of carbonyl compounds and acids. With the Mn salt of picolinic acid, the oxidation mainly gives esters.

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