Heteroadamantanes and their derivatives. 6. Synthesis and mass-spectrometric investigation of 5-mono- and 5,6-disubtituted 6-oxo-1,3-diazaadamantanes

The corresponding 5-mono- and 5,7-disubstituted 6-oxo-1,3-diazaadamantanes were obtained with high yields by the condensation of mono- and ,'-disubstituted acetones with hexamethylenetetramine in the presence of glacial acetic acid, and their structures were confirmed by IR and PMR spectra. The behavior of the compounds under electron impact was studied, and the main fragmentation paths of their molecules were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1679–1685, December, 1985.     

Purification of nerve growth factor from the venom of the Central Asian cobraNaja oxiana

A highly purified electrophoreticaly homogeneous protein with a NGF activity of 10·10⁵ BU/mg of protein have been isolated from the venom of the Central Asian cobra by gel-filtration and ion-exchange chromatography followed by preparative isolectric focusing in a thin layer of Sephadex. It has been shown that the NGF isolated is characterized by a molecular weight in the range of 20–30 kD and a pI value of about 7.0.     

Synthesis of new-type 1,3,6-triazocine via intramolecular reactions of iodocyclization and [3+2] azido cycloaddition

Selective iodocyclization of 6-(alkenylamino)-1-allylpyrazolo[3,4-d]pyrimidines provided hydrogenated derivatives of 1-allyl-8(9)-iodomethylimidazo(pyrimido)[1,2-a]pyrazolo[4,3-e]pyrimidines which were further reacted with NaN₃ at 75°С to 80°С to give a series of new-type 1,3,6-triazocines annulated with the pyrazole, pyrimidine, imidazole (or pyrimidine), and 1,2,3-triazole rings. The compounds synthesized were structurally characterized by analytical, spectral (IR, ¹H and ¹³C NMR, HPLC-mass), and X-ray diffraction data.     

Production of Gold nanoparticles in aqueous solutions of cellulose derivatives

It is shown that gold nanoparticles can be produced using cellulose ethers, methylhydroxyethyl cellulose, and carboxymethyl cellulose as reducing agents that also play the role of nanoparticle stabilizers. Depending on the synthesis conditions, nanoparticle sizes vary in the range of 20–100 nm. The application of carboxymethyl cellulose as a stabilizer may give rise to the formation of a bimodal ensemble of nanoparticles with sizes of 4–5 and 30–40 nm. The differences in the mechanisms for the reduction and stabilization of gold nanoparticles in the presence of these cellulose derivatives are established by IR spectroscopy. The obtained colloidal dispersions of gold nanoparticles remain stable for a long time.     

Synthesis of the Anti‐HIV Agent (−)‐Hyperolactone C by Using Oxonium Ylide Formation–Rearrangement

Starting from readily available (S)‐styrene oxide an asymmetric synthesis is described of the naturally occurring anti‐HIV spirolactone (?)‐hyperolactone C, which possesses adjacent fully substituted stereocenters. The key step involves a stereocontrolled Rh^II‐catalysed oxonium ylide formation–[2,3] sigmatropic rearrangement of an α‐diazo‐β‐ketoester bearing allylic ether functionality. From the resulting furanone, an acid‐catalysed lactonisation and dehydrogenation gives the natural product.     

Catalysis of nucleophilic substitution reactions in supramolecular systems

The factors determining the catalytic effect of supramolecular systems on the nucleophilic substitution reactions are analyzed. The role of the structural and phase transitions of nanoaggregates in the catalytic mechanism are determined. The substrate specificity is shown for different structures of the supramolecular composition.     

Synthesis of alkyl (α-phenylthioalkenyl) ketones containing a (Z)-trisubstituted olefinic fragment

Warren"s method, which has been proposed for the synthesis of -phenylthiodialkyl ketones, appeared to be inefficient for the preparation of their alkenyl alkyl analogs. The latter were prepared in good yields by alkenylation of alkyl phenylthiomethyl ketones with alkenyl bromides.     

Fused polycyclic nitrogen-containing heterocycles 11. 4-Hydroxy-3,5-diphenyl-2-phenyliminothiazolidines as new key compounds in the synthesis of thiazolo[3,4-<Emphasis Type="Italic">a</Emphasis>]quinoxaline derivatives

A procedure was developed for the synthesis of thiazolo[3,4-a]quinoxaline derivatives based on a new strategy for construction of the pyrazine ring. The key step of the process involves the reaction of 4-hydroxy-3,5-diphenyl-2-phenyliminothiazolidines with o-phenylenediamines.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2462–2470, November, 2004.     

Synthesis of uronoyldipeptide derivatives of N-acetylglucosamine and of N-acetylmuramoyldipeptide

Starting from benzyl 3,4-di-O-acetyl-6-O-trityl-N-acetyl--glucosamine and benzyl -benzyl-4-O-acetyl-N-acetylmuramate, 2-acetamido-2-deoxy-D-glucopyranuronyl-L-alanyl-D-isoglutamine and O-(2-acetamido-2-deoxy-D-glucopyranuronyl-L-alanyl-D-isoglutamin-3-yl)-D-lactoyl-L-alanyl-D-isoglutamine — uronoyldipeptide analogs of N-acetylglucosamine and N-acetylmuramoyl dipeptides — have been synthesized.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 850–855, November–December, 1988.