Novel polycyclic heterocycles. XI. Synthesis of 11,12-dihydropyrido[2,1-b] [1,3]benzodiazepines, 6H-pyrido[1,2-c] [1,3,5]benzoxadiazepines,and 6H-Pyrido[1,2-c] [1,3,5]benzothiadiazepines

An unusually facile dehydrobromination, involving the ortho-bromine atom and the = NH proton of a 2-imino-1-(phenethyl)-, 2-imino-1-(phenoxymethyl)-, or 2-imino-1-(phenylthiomethyl)-pyridine ( 2a-e ) has led to the synthesis of three novel bridgehead nitrogen tricyclic systems: 11,12-dihydropyrido[2,1-b] [1,3]benzodiazepines ( 3a,b ), 6H-pyrido[1,2-c] [1,3,5]benzoxadiazepines ( 3c,d ) and 6H-pyrido[1,2-c][1,3,5]benzothiadiazepines ( 3e ). As anticipated, these cyclizations required a base, e.g., potassium carbonate, and a catalyst, e.g., copper bronze. What was unusual, was that these reactions occurred in methanol or n-propanol, under reflux, either under anhydrous conditions, or in the presence of large amounts of water. The pmr spectra of these compounds are discussed.     

Ring transformation of 6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine. VI. Substituent effect of 6-substituted 5a-acetyl-6a-ethoxycarbonyl-5a,6a- dihydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine-3-carbonitriles

Synthesis and reactivity of 6-ethoxycarbonyl-, 6-phenyl- and 6-methyl-5a-acetyl-6a-ethoxycarbonyl-5a,6a-di-hydro-6H-cyclopropa[e]pyrazolo[1,5-a]pyrimidine-3-carbonitriles 4 , 5 , and 7 are described.     

Characterization of precursors of p-tert-butylcalix[6]arene synthesis. Mechanism of formation of p-tert-butylcalix[6]arene

Abstract

Gutsche has proposed the existence of “hemicalixarenes” and “pseudocalixarenes” to explain the formation of calixarenes. The characterization and the quantitative determination of molecules present during the reaction, described in “Organic Synthesis”, have permitted us to determine the immediate precursors of p-tert-butylcalix[6]arene. The calix[6]arene could be due to cyclization of linear species named “pseudocalixarenes” and not due to duplication of molecules named “hemicalixarenes”.     

Crystal engineering in ionic liquids. The crystal structures of [Mppyr]3[NdI6] and [Bmpyr]4[NdI6][Tf2N

Single crystals of [mppyr][NdI6] and [bmpyr][NdI6][Tf2N] are the first surprising examples of how the cation of an ionic liquid determines the compound formation from an ionic liquid. Depending upon the variation of the length of the alkyl chain of the quaternary pyrrolidinium cation (C3 and C4, respectively), incorporation of the anion of the ionic liquid, [Tf2N]-, can either be evoked or suppressed.     

Synthesis of 6-phenyl and 6-styrylthiazolo[3,2-b] [1,2,4]triazoles

Thiazole rings have been often encountered in the structure of antibiotic or antitumor drugs. An easy synthesis of them has revealed itself necessary in order to elucidate the mechanism of action of these naturally occurring substances. A method of preparation of conjugated b-ethylenic thiazole[3,2-b] [1,2,4]triazoles by heating a 3-thio substituted [1,2,4]triazole in the presence of polyphosphoric acid is reported here, giving the expected product in a 60% yield.     

Chemistry of furazano[3,4-b]pyrazine. 5. 1,2,3-Triazolo[4,5-e]furazano[3,4-b]pyrazine 6-oxides

New representatives of a little-investigated class of compound-1,2,3-triazole 2-oxides — were obtained by a nonphotochemical method. Mononitroamines and dinitroamines are produced during their formation as intermediate products. For Communication 4, see [1]. Latvian Institute of Organic Synthesis Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii. No. 11, pp. 1565–1570. November, 1997.     

Indolobenzo[b]furans. 3. Synthesis of unsubstituted indolo[7′,6′∶2,3]- and indolo[6′,7′∶2,3]benzo[b]pyrans

Indolo[7,62,3]- and indolo[6,72,3]benzo[b]furans have been synthesized with the aid of the Fischer reaction. The physicochemical characteristics of the compounds synthesized are considered.For communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 631–634, May, 1985.     

Synthesis of hydroxy-6H-benzofuro[3,2-c] [1]benzopyran-6-ones

The Micheal addition of ethyl 2-methoxy-, 2,4-dimethoxy- and 2,5-dimethoxybenzoylacetates with benzoquinone leads to ethyl 2-(rnethoxy or dimethoxy phenyl)-5-hydroxybenzofuran 3-carboxylates. Treatment of the henzofuran derivatives with anhydrous pyridine hydrochloride at 190–195° leads to hydroxy-6H-henzofuro[3,2-c] [1]benzopyran-6-ones.     

Spectrophotometric study of the supramolecular complexes of [60]- and [70]Fullerenes with biscalix[6]arene and crown[4]calix[6]arene

[60]- and [70]Fullerenes have been shown to form 1:1 supramolecular complexes with bis[2-(5,11,17,23,29,35-hexa-tert-butyl-37,38,39,40,41-pentahydroxycalix[6]arenyl-oxy ethyl ether) (1) and 5,11,17,23,29,35-hexa-tert-butyl-37,38,40,41-tetra hydroxyl-39,42-(crown-4)calix[6]arene (2) in CHCl3 medium by electronic absorption spectroscopy. Formation constants (K) of the complexes of [60]- and [70]fullerenes with 1 and 2 have been determined at room temperature from which free energy of formation values of the complexes have been estimated. The very high formation constant value of [60]fullerene/1 complex (5900 dm3 mol-1) in indicative of formation of inclusion complex. Moreover, PM3 calculations reveal that intermolecular interaction between [60]fullerene and 1 proceeds through quite deep energy molecular orbital.     

Chemistry of furazano[3,4-b]pyrazine 6. 1,2,3-triazolo[4,5-b]furazano[3,4-b]pyrazines

The reduction of 1,2,3-triazolo[4,5-e]furazano[3,4-b]pyrazine 6-oxide was investigated. By means of data from x-ray crystallographic analysis it was shown that there is a relation between the aromaticity and the structure of the obtained triazoles.For communication 5, see [1].Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1259–1264, September, 1998.     

K6[Mn2O6] und K6[Fe2 O6] - ein Vergleich

K₆[Mn₂O₆] and K₆[Fe₂O₆] - a Comparison K₆[Mn₂O₆] has been prepared (dark-red single crystals). The structure (a = 8.88₆, b = 6.76₀, c = 11.39₄ Å, γ = 132.1°, space group P2₁, Z = 2, 1151 symmetry independent reflections hk0–hk9, R = 0.051) shows Al₂Cl₆-like anions [Mn₂O₆]^6?. By unit-cell transformation to the monoclinic setting P2₁/a (a = 6.76₀, b = 11.39₄, c = 6.63₈ Å, β = 96,9°) the structural similarity to K₆[Fe₂O₆] becomes evident. The Madelung Part of Lattice Energy, MAPLE, is calculated.     

Ion Complexation Properties of Calix[6]Arene Derivatives: I. 1,4-Calix[6]Crown-4 Derivatives

Abstract

A series of 1,4-p-tert-butyl-calix[6]crown-4 tetraesters, tetraamides, tetraacids with defined conformation have been synthesized, and their complexation properties towards metal ions and alkyl ammonium ions were investigated systematically. It was found that 1,4-p-tert-butyl-calix[6]crown-4 tetraethylester (3a) and 1,4-p-tert-butyl-calix[6]benzocrown-4 tetramethyl-ester (4b) show high selectivity towards Na⁺, Li⁺, respectively and all of them exhibit high complexation abilities towards Et₂NH₂ ⁺ cation.     

Oxa bowls: studies toward hexaoxa-[6]-peristylane. Synthesis of a seco-derivative of hexaoxa-[6]-peristylane

When the concept of equivalency of all-cis-[n]-formyl-[n]-cycloalkanes with [n]-oxa-[n]-peristylanes was followed, an approach to the "oxa bowl" hexaoxa-[6]-peristylane 4a was delineated. This required an access to all-cis-cyclohexane-hexacarbaldehyde 5, which could be subjected to a 6-fold intramolecular acetalization cascade. A readily available Diels-Alder adduct of cyclooctatetraene and maleic anhydride was chosen as the starting material and was elaborated to the endo, endo-tetraene 6 in which all the six aldehyde functionalities are present in a latent form with cis orientation in a locked cyclohexane ring. Although ozonolysis of 6 has so far led only to intractable products, the novelty and brevity of our approach have been demonstrated through the intramolecular acetalizations through ozonolysis in 7 and 15, leading to oxa bowls 9 (seco-hexaoxaperistylane) and 16, respectively. The formation of 9 and 16 requires the generation of five tetrahydrofuran and four oxacyclic rings, respectively, in a single-pot operation.     

Polycyclic azetidines. I. The preparation of benzo [c]-cis-6-azabicyclo[3.2.0] heptane

The title compound was prepared from compounds readily obtained from 2-carbomethoxy-I-indanone oxime ( 5 ) or from the N-chlorosulfonyl isocyanate adduct of indene ( 9 ). Apart from its ability to undergo transformation to the azetidine, compound 9 upon refluxing with excess LAII was found to undergo reductive decompostion to cis-2-hydroxymethyl-1-indanamine ( 2 ).