Theoretical study of the pathway for diazine ring formation in a series of 4-dimethylaminonaphthalic acid derivatives under Vilsmeier-Haack reaction conditions

Using the semiempirical quantum-chemical PM3 method, we have studied the formation of a quaternized diazine ring in a series of 4-dimethylaminonaphthalic acid derivatives under Vilsmeier-Haack reaction conditions. We have established that the reaction may occur via a two-step cycloisomerization of the intermediate Vilsmeier adduct, through six-center cyclic transition states. Institute of Single Crystals, National Academy of Sciences of Ukraine, 60 Prospekt Lenina, Khar'kov 310001, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 36, No. 4, pp. 201–205, July–August, 2000.     

Acylation of 5-phenyl-2-(fur-2-yl)oxazole

The ability of 5-phenyl-2-(fur-2-yl)oxazole to undergo acetylation and formylation is considered. It was established by x-ray structure analysis that electrophilic substitution proceeds at the position 5 of the furan ring. The direction of the reactions is analyzed from positions of the energy preference of transition states. Institute of Monocrystals, Academy of Sciences (NAN) of Ukraine, Khar'kov 310001. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1466–1471, November, 1997.     

Recyclization of 2-imino-2H-1-benzopyrans using nucleophilic reagents 3. Reaction of 2-iminocoumarin-3-carboxamides with o-phenylenediamines and o-amino(thio)phenols

Using o-phenylenediamines, o-aminophenol or o-aminothiophenol, 2-iminocoumarin-3-carboxamide can be recyclized to the corresponding 3-(1H-benzimidazol-2-yl), 3-(benzoxazol-2-yl), or 3-(benzothiazol-2-yl) coumarins. An alternative synthesis has been carried out and an analytical comparison of the synthetic routes made. For Communication 2 see [2]. Ukraine Pharmaceutical Academy, Khar'kov 310002. E-mail: kosn@ukrfa.kharkov.ua. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1664–1667, December, 1998.     

Carbohydrates of the inflorescences of Calendula officinalis

All-Union Scientific Research Institute of the Chemistry and Technology of Medicinal Plants, Khar'kov. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 585–586, July–August, 1988.     

Synthesis of rhamnosides from erysimin and helveticosol

G. S. Skorovoda Khar'kov State Pedagogic Institute. State Scientific Center for Drugs. 310085, Khar'kov-85, ul. Astronomicheskaya, 33. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 569–570, July–August, 1994.     

Coumarins of Matricaria recutita

All-Union Scientific-Research Institute of Drug Chemistry and Technology, Khar'kov. Translated from Khimiya Prirodnykh Soedinenii, No. 6, p. 853, November–December, 1991.     

New semisynthetic cardiac glycosides and their biological activity

Digitoxigenin, digitoxin, D-xylose and L-rhamnose have been used as the starting materials for the synthesis of the new cardiac glycosides: digitoxigenin 3-O-β-D-xylopyranoside and digitoxin 4‴-O-α-L-rhamnopyranoside. It has been established that the compounds obtained possess comparatively high biological activities. All-Union Scientific-Research Institute of Drug Chemistry and Technology. Khar'kov Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 776–779, November–December, 1990.     

Recyclization of 2-imino-2H-1-benzopyrans by the action of nucleophilic reagents 4. Use of 2-(N-aroylhydrazono)coumarin-3-carboxamides for the synthesis of 3-(1,3,4-oxadiazol-2-yl)coumarins

A new method for the synthesis of 3-(1,3,4-oxadiazol-2-yl)coumarins is proposed. It is based on the recyclization of 2-(N-aroylhydrazono)coumarin-3-carboxamides, which are readily obtained by the reaction of 2-iminocoumarin-3-carboxamides with arenecarboxylic hydrazides in an acidic medium. Advantages of the given method over alternative synthetic schemes were shown. Proposals on the mechanism of reaction were made.For Communication 3, see [1].Ukrainian Pharmaceutical Academy, Khar'kov 310002. Khar'kov State University, Khar'kov 310077, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 190–193, February, 1999.     

New reactions of cyclization and recyclization of derivatives of 1,3-dimethyl-5,6-diaminouracil

The reaction of 1,3-dimethyl-5-6-diaminouracils with chalcones produced 7,9-dimethyl-2,4-diaryl-1-,7,9-triazaspiro[4,5] decene-1-6,8,10-triols. The transformation of these spiro-compounds to pyrimido[4,5-d]oxazoles was investigated.Khar'kov State University, Khar'kov 31007. Institute of Single Crystals, Academy of Sciences of Ukraine, Khar'kov 310141. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 972-983, July, 1996. Original article submitted February 20, 1996.     

Spectral and luminescence properties of derivatives of 2-aryl[9,10]phenanthroxazole

Certain 2-aryl derivatives of [9,10]phenanthroxazole have been synthesized and their spectral and luminescence properties have been investigated. It has been shown that the introduction of acceptor substituents into the para position of the 2 -phenyl radical changes the nature of the fluorescence state, resulting in a nearly two-fold increase of the rate constant of fluorescence emission and a 50% increase of the quantum yield of fluorescence. Special features of the spectral and luminescence properties have been examined for derivatives with an intramolecular hydrogen bond (aryl = o-hydroxyphenyl) and with considerable steric hindrance (aryl = 9-anthryl).Khar'kov State University, Khar'kov 310077. Institute of Single Crystals, National Academy of Sciences of the Ukraine, Khar'kov 310001. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 558–566, April, 1995. Original article submitted February 23, 1994.     

Conformational features of peptide fragments of the C-end of histone H1

The conformational possibilities of four synthesized oligopeptides with the amino acid sequences 165–172, 173–184, 152–172, and 152–184 of the C-end of histone H1 of calf thymus above been studied in solution under various conditions by the method of circular dichroism. V. I. Nikitin Institute of Chemistry, Academy of Sciences of the Tadchik SSR, Dushanbe. Institute of Cytology, Academy of Sciences of the USSR, Leningrad. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 793–798, November–December, 1990.     

A chemical study of plants of the Mongolian flora the flavonoids of two species of Oxytropis

Institute of Chemistry, Mongolian Academy of Sciences, Ulan-Bator. Institute of the Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 722–723, November–December, 1992.     

Refinement of the crystal and molecular structure of 4-phenylthiosemicarbazide diacetic acid monohydrate

Institute of Applied Physics, Academy of Sciences, Moldova Republic. Institute of Chemistry, Academy of Sciences, Moldova Republic. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 3, pp. 154–158, May–June, 1994.     

Construction of crystal structure sections using the clat software package

Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Institute of Physical Chemistry, Polish Academy of Sciences. Translated fromZhurnal Struktumoi Khimii, Vol. 36, No. 5, pp. 956–959, September–October, 1995.     

Coordinated diaminoguanidinium(1+) ion in the crystal structure of the [Cu(CH8N5)Cl3] complex

Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Institute of Organoelement Compounds, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 5, pp. 936–941, September–October, 1995.     

Triterpene glycosides of Scabiosa soongorica. V. β-Sitosterol β-D-glucopyranoside and songoroside A

Institute of Organic Chemistry, Academy of Sciences of the Kirgiz SSR, Frunze. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 885–886, November–December, 1988.     

Production of (+)-norsolanadione

Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Russian Academy of Sciences, Ufa. Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 735–736, September–October, 1991.     

Structural,vibrational, and energy characteristics of halide molecules of group II–V elements

Correlations between the internuclear distances r(M-X), the bond energies E(M-X), and the valence force constants f_r for di- and trihalides of Group II–V elements are established. Some missing values are estimated. Ivanovo State Chemical Technological Academy. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 5, pp. 859–875, September–October, 1996. Translated by L. Smolina Ivanovo State Chemical Technological Academy. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 5, pp. 859–875, September–October, 1996.     

Structural conversions of rhodamines in solution

A study has been made of the acidic ionization, structural conversions, and prototropic tautomerism of rhodamine chromogens in methanol and dimethyl sulfoxide, using IR, ¹³ C NMR, and electronic spectroscopy. The lactone structure has been established for the colorless form of rhodamines in DMSO. For rhodamine B in mixtures of water with DMSO, the lactone/zwitterion ratio has been estimated.V. I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow 117975. Khar'kov State University, Khar'kov 310077. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 512–521, March, 1992.     

Crystal and molecular structure of 1-(2′-methoxyphenyl)-3,7,10-trimethylstannatrane

A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences. Irkutsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 5, pp. 199–203, September–October, 1994.