Intracavity laser polarization spectrometer for biomolecule traces

A polarization variant of an intracavity laser spectrometer based on the competition of beams in an argon ion laser, radiating a number of narrow lines in the 275 to 529 nm spectral range, is proposed and described for the spectral analysis of liquid samples, having broad absorption bands, mainly biomolecules in solutions. By careful optimization of the operating conditions, a procedure has been established that results in a minimal measurable absorbance decreased up to 10(-5) units of optical density. The examined spectrometer provides a wide dynamic range of analysis. A determination of trace contents of amino acids in methanol were carried out.     

Photochemical properties and structures ofN-amino andN-azomethine derivatives of 2,4,6-triphenylpyridinium perchlorates

The molecular structures of the initial compounds and the products of photocyclization involving amino and azomethine groups in perchlorates ofN-amino (1) andN-azomethine (2) derivatives of 2,4,6-triphenylpyridinium cations were studied. Cations1 and2 have an essentially non-coplanar arrangement of the -Ph rings, and the product of photocyclization of2, cation3, is characterized by a flattened structure. It was found that the orientation of the lone electron pair of the N atom with respect to one of the planes of the -Ph rings in molecule1 is more favorable for monocyclization involving the amino group. The structure of molecule2 allows two routes of the photoreaction,viz., O N proton transfer and monocyclization with an -Ph ring. However, the structural features of molecule2 are more favorable for photocyclization.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 296–301, February, 1995.     

Reaction of 2-chloro-5-methylbenzoquinone with Β-aminocrotonic ester derivatives

The reaction of 2-chloro-5-methylbenzoquinone with -aminocrotonic ester derivatives was studied by PMR spectroscopy in CD₃COOD. The spectra indicate the formation of intermediate hydroquinone and quinone derivatives, which subsequently transform into the corresponding indoles. It was shown that the indolization proceeds unequivocally at the 3-position of the initial benzoquinone, and the rate of formation of the indole derivatives decreases with increase in the size of the substituent at the nitrogen atom of the -aminocrotonic ester. The starting, intermediate compounds and the end products observed in the PMR spectra were identified by comparison with specially synthesized compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 324–328, March, 1990.     

Reaction of 2,3-epoxypropyl alkyl sulfides with carboxylic acids and phenol

Russian Chemical Bulletin -     

Mass-spectrometric study of the cyclization of diazo ketones. 2. Cyclization of 1-diazo-4-sulfonylaminobutan-2-ones to N-sulfonylpyrrolidin-3-ones

A comparison of the mass spectra of 1-diazo-4-sulfonylamino-butan-2-ones and N-sulfonylpyrrolidin-3-ones makes it possible to conclude that under the conditions of electron impact and chemical ionization the molecular ions of the investigated diazo ketones lose a molecule of nitrogen and undergo partial cyclization to the corresponding pyrrolidinones without undergoing the Wolff rearrangement.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 919–925, July, 1982.