Synthesis of bacterial antigenic polysaccharides and their fragments V. Use of 1,2-o-isopropylidene-4,6-O-ethylidene-α-D-galactopyranose for the synthesis of oligosaccharides with 3-o-substituted galactopyranose residue

Conclusions Trisaccharide-D-glucopyranosyl-(14)--L-rhamnopyranosyl-(1 3)-D-galactose was synthesized by using, 2-O-isopropylidene-4,6-O-ethylidene--D-galactopyranose for producing 1 3-rhamnosylgalactose, linkage.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1609–1613, July, 1977.     

Synthesis and oxidation of 2,6-dimethyl-3, 5-di(phenoxycarbonyl)-1,4-dihydropyridines

A number of new aryl esters of acetoacetic acid were obtained in the reaction of phenols with diketene in the presence of triethylamine. Reaction of the esters thus obtained with hexamethylenetetramine gave, for the first time, aryl esters of 1,4-dihydropyridine-3,5-dicarboxylic acid, the oxidation of which with chloranil gave the corresponding pyridines.     

Correlation effects and interaction energy of π-electron shells in cumulene and acetylene molecules

By means of Hartree—Fock energy variance calculations it has been shown that the specific electroncorrelation energy in extended cumulene molecules is approximately 0.3 eV/electron and the specific energy of interaction between -electron shells is 0.1 eV/electron.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 29, No. 6, pp. 514–517, November–December, 1993.     

Methylation of the cyclic homolog of xanthine

Alkylation of the cyclic homolog of xanthine in the methyl iodide-sodium hydride system as a function of the reagent-alkylating system ratio yields different products: for a 13 ratio of reagents, a homolog of caffeine is formed, while for a 12 ratio, a homolog of theobromine is formed. In contrast to xanthine, methylation of its cyclic homolog initially takes place at the imidazole ring and occurs in the sequence N₍₁₎, N₍₄₎, N₍₇₎.A. V. Bogatskii National Academy of Sciences of Ukraine, Odessa 270080. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 701–703, May, 1998.     

Silyl modification of biologically active compounds. 3. organosilicon derivatives of aminoalcohols in the series of tetrahydroquinoline,tetrahydroisoquinoline, and tetrahydrosilaisoquinoline

The N-(2-hydroxyethyl)-1, 2, 3, 4-tetrahydroquinoline, -isoquinoline, and -silaisoquinoline, and their trimethyland triethylsilyl derivatives and the corresponding methiodides were synthesized. The acute toxicity and psychotropic activity of the compounds synthesized were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 793–799, June, 1996. Original article submitted April 25, 1996.     

Derivatives of heterocyclic α-iminocarboxylic acids. 4. Reduction of N-alkoxycarbonyl derivatives of α-iminocarboxylic acids

When N-methoxycarbonyl and N-benzoxycarbonyl derivatives of methyl esters of aziridine-2-carboxylic acid, L-proline, L-thioproline, and pipecolic acid interact with NaBH₄ in tert-butanol/methanol, the products of reduction of the C-methoxycarbonyl group of the original compounds are accompanied by bicyclic urethanes and oxazolidines. Reduction of N-maleates and N-fumarates of heterocyclic -iminocarboxylic acids leads to the formation of -hydroxymethyl-N-[4-(2-oxo-2,5-dihydrofuryl)] derivatives of pyrrolidine, piperidine, 1,3-thiazolidine, and 1,4-thiazan. In the latter case, 1-aza-2-hydroxymethyl-4-oxo-5-oxa-9-thiabicyclo [5.4.0]undecene-2 is also obtained. The N-maleates and fumarates of aziridine-2-carboxylic acid are reduced anomalously by sodium borohydride, forming 2-hydroxymethyl-2-(-hydroxyethyl)-3-oxa-1-azabicyclo[3.1.0]hexanes.For Communication 3 see [2].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1567–1573, November, 1993.     

Recyclization of tetranitrodibenzo-18-crown-6 and tetranitrodibenzo-24-crown-8 into monobenzocrown ethers

The benzo-9-crown-3 and benzo-12-crown-4 derivatives are formed by reaction of tetranitrodibenzo-18-crown-6 and tetranitrodibenzo-24-crown-8, respectively, with sodium methoxyethoxide in DMSO at 20C.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1474–1476, November, 1990.     

A chemical investigation ofMatteuccia struthiopteris

Irkutsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 608–609, July–August, 1993.     

Synthesis and structure of 5-methyl-1-(2-R-phenyl)-dihydro-2,4(1H,3H)-pyrimidinediones and their 2-thiono analogs

The reaction of o-substituted aromatic amines with methacrylic acid gave N-aryl--methyl--alanines, which were converted to dihydro-2,4-pyrimidinedione and dihydro-4-pyrimidinone-2-thione derivatives. The alkylation, acylation, and oximation of the dihydro-2,4-pyrimidinediones were accomplished. Conformational analysis of the compounds obtained was carried out by dynamic NMR methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1240–1247, September, 1991.     

Benzenoid-quinoid tautomerism of azomethines and their structural analogs. 43. Phenylmercury derivatives of 3-hydroxy-2-acetyl(benzoyl)benzo[b]thiophene and 3-hydroxy-1-methylindole-2-carbaldehyde imines

Phenylmercury derivatives of 3-hydroxy-2-acetyl(benzoyl)benzo[b]thiophene and 3-hydroxy-1-methyl-2-carbaldehyde N-aryl- and N-alkylimines, to which a keto enamine structure with strong intramolecular coordination of the mercury atom and the carbonyl oxygen atom was assigned on the basis of the electronic and vibrational spectra, were synthesized. Compounds of the indole series fluoresce intensely with the usual values of the Stokesian shifts.See [1] for Communication 42.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 596–599, May, 1989.