Synthetic researches in the field of curare alkaloids XVIII. Synthesis of the methiodide of 1,3,4-(1′hydroxy-3′-methyl-4′-ethylidenepentane-1′, 3′, b, 5′-triyl)-3, 4, 5, 6-tetrahydro-β-carboline

The methiodide of 1,3, 4-(1′-hydroxy-3′-methyl-4′-ethylidenepentan1′, 3′, b, 5′-triyl]-3,4, 5, 6-tetrahydro-β-carboline is synthesized.     

Catalytic alkylation of cycloalkaneindoles and tetrahydro-γ-carboline with 9-oxiranylmethylcarbazole

Catalytic alkylation of substituted indoles such as cycloalkaneindoles and tetrahydro-γ-carboline using 9-oxiranylmethylcarbazole leads to the formation of 1-(carbazol-9-yl)-3-{dihydrocycloalkane[b]indol-4(1H)-yl}propan-2-ols and 1-(carbazol-9-yl)-3-{2,8-dimethyl-3,4-dihydro-1H-pyrido[4,3-b]indol-5(2H)-yl}propan-2-ol, conjugates containing 2-hydroxypropylene spacer.     

Convenient Way to the Synthesis of Polycyclic Fused Benzimidazole Derivatives with a Bridgehead Nitrogen Atom

Effective synthesis was developed for 1,2,3,4-tetrahydropyrido- and pyrido[1,2-a]benzimidazole-7,8-diamines that underlie the preparation of new polyazaheterocycles: pyrido[1,2-а]imidazo[4,5-f]-benzimidazole, 7Н-pyrido[1,2-а]imidazo[4,5-f]benzotriazole, pyrido[1,2-а]imidazo[4,5-g]quinoxaline.     

Synthesis of New Heterocyclic Systems on the Basis of 7-Benzyl-3-chloro-1-(morpholin-4-yl)-5,6,7,8-tetrahydro-2,7-naphthiridine-4-carbonitrile

Methods have been developed for the synthesis of new 8-amino-3-benzyl-5-(morpholin-4-yl)-1,2,3,4-tetrahydropyrimido[4′,5′: 4,5]thieno[2,3-c][2,7]naphthyridine starting from 7-benzyl-3-chloro-1-(morpholin-4-yl)-5,6,7,8-tetrahydro-2,7-naphthyridine-4-carbonitrile. 8-Hydrazinyl-3-benzyl-5-(morpholin-4-yl)-1,2,3,4-tetrahydropyrimido[4′,5′: 4,5]thieno[2,3-c][2,7]naphthyridine has been converted to isomeric pentacyclic structures with a triazole ring fused through the [c] side of the pyrimidine ring, and their Dimroth rearrangement has been accomplished in both acidic and basic media. New heterocyclic systems containing pyrrolo[1,2-a]pyrimidinone and pyrimido[1,2-a]azepinone fragments were obtained on the basis of the thieno-[2,3-c][2,7]naphthyridine derivative.     

Reactions of 2,3-dioxopyrrolo[2,1-<Emphasis Type="Italic">a</Emphasis>]isoquinolinecarboxylic acid esters and amides with nitrogen-centered nucleophiles

Reactions of ethyl 2,3-dioxopyrrolo[2,1-a]isoquinoline-1-carboxylates with active nitrogen-centered nucleophiles (phenylhydrazine, hydroxylamine, and benzylamine) involve opening of the pyrrole ring with formation of 2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-N′¹,N′⁴-diphenyl-3-(2-phenylhydrazono) succinohydrazide, 5-(6,7-dimethoxy-3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-2,3,4,5-tetrahydro-1H-1,2-oxazine-3,4,6-trione, and ethyl 4-benzylamino-2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-3,4-dioxobutanoate, respectively. Cyclic amides derived from 5,5-dimethyl-2,3-dioxo-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-1-carboxylic acid react with benzylamine in a similar way. Reactions of the title compounds with weaker nucleophiles, such as semicarbazide and thiosemicarbazide, are not accompanied by opening of the pyrrole ring, and the products are the corresponding semicarbazones and thiosemicarbazones at the C²=O carbonyl group.     

Derivatives of α,β-dehydroamino acids: V. Intramolecular cyclization of 2-{2-[(<Emphasis Type="Italic">Z</Emphasis>)-1-Benzamido-2-phenylvinyl]acetamidomethyl}benzimidazole

Reaction of 4-benzylidene-2-phenyl-1,3-oxazol-5(4H)-one with 2-(1H-benzimidazol-2-yl)ethaneamine led to the formation of 2-{2-[(Z)-1-benzamido-2-phenylvinyl]acetamidomethyl}benzimidazole that in a reaction with hexamethyldisilazane in DMF gave 5-benzylidene-1-(1H-benzimidazol-2-yl)-2-phenyl-3,5-dihydro-4H-imidazol-4-one. In the presence of K₂CO₃ in dioxane the reaction with hexamethyldisilazane resulted in the product of intramolecular addition, N-(4-benzyl-3-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]-benzimidazol-4-yl)benzamide     

Quantum chemical studies of azoles 3. Thermodynamic stabilities of neutral molecules and intermediates formed in electrophilic substitution of azoles containing three or four heteroatoms

Density functional theory quantum chemical calculations of thermodynamic stabilities in the gas phase and in water were carried out for 1,3,4-oxadiazole and 1,3,4-thiadiazole, 1,2,4-1H-triazole and 1,2,4-4H-triazole, 1,2,3,4-1H-tetrazole and 1,2,3,4-2H-tetrazole molecules, and for cationic and bipolar (carbenoid) intermediates formed by these molecules in electrophilic substitution reactions (with proton as model electrophile) and the results obtained are compared. Differences in the chemical behavior of pairs of isomeric 1H- and 4H-1,2,4-triazoles and 1H- and 2H-tetrazoles are analyzed.     

Hetero-Diels–Alder Reaction of Aroylpyrrolo[1,2-<Emphasis Type="Italic">a</Emphasis>]quinoxalinetriones with Styrene

Hetero-Diels–Alder reaction of 3-aroylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones with styrene afforded diastereoisomeric (5R*,6aR*)- and (5S*,6aR*)-3,5-diaryl-5,6-dihydropyrano[4′,3′:2,3]pyrrolo[1,2-a]-quinoxaline-1,2,7(8H)-triones.     

Crystal structure and antitumor activities of a dinuclear cobalt(II) complex based on <Emphasis Type="Italic">meso</Emphasis>-1,2,3,4-tetra(1H-benzo[<Emphasis Type="Italic">d</Emphasis>]imidazol-2-yl)butane

The [Co₂(tbb)Cl₄]?4DMF complex, where tbb is meso-1,2,3,4-tetra(1H-benzo[d]imidazol-2-yl)butane, is synthesized and characterized by single crystal X-ray diffraction. For the complex: C₄₄H₅₄Co₂C_l4N₁₂O₄, M_r = 1074.65, monoclinic crystal system, space group P21/n, a = 9.2350(13) Å, b = 11.3566(15) Å, c = 23.879(3) Å, β = 90.547(2)°, V = 2504.3(6) ų, Z = 2, D_c = 1.425 g/cm³, λ = 0.71073 Å, μ(MoK_α) = = 0.929 mm^–1, F(000) = 1112, S = 1.047, R = 0.0765, and wR = 0.2110 for 13668 observed reflections with I > 2σ(I). It is a neutral dinuclear complex. One meso-1,2,3,4-tetra(1H-benzo[d]imidazol-2-yl)butane coordinates two cobalt(II) ions. Each cobalt(II) ion is formed by two tbb nitrogen atoms and two chloride ions. The antiproliferative activities of the complex are screened by MTT assay against Eca109 cancer cells. The complex exhibits inhibition on the growth of Eca109 cancer cells with IC₅₀ of 22.1±6.7 μM after 48 h treatment. The cobalt complex has potential application in treatment of Eca109 cancer. CCDC 1015791.     

New derivatives of 4-quinaldinol

The reactions of 1, 1, 3-trichloro-1-propene and also 1, 1, 1-trichloro-2-propene with acetoacetic ester gave α-(γ, γ-dichlorallyl)acetoacetic ester (I). In the reactions with aniline and o- and p-toluidines, the corresponding α-(γ, γ-dichloroallyl)-β-arylamino-crotonic esters were produced, thermal cyclization of which gave 2-methyl-3-(γ, γ-dichloroallyl)-4-hydroxyquinoline (II) and its 6CH₃- (III) and 8CH₃- (IV) homologs. With phosphorus oxychloride, II–IV gave the corresponding 4-chloro-substituted quinolines (V–VII); with concentrated sulfuric acid, II–VII were converted into the corresponding β-quinolinylpropionic acids VIII–XIII.     

Diastereoselective 1,3-Dipolar Cycloaddition of Nitrones to 1<Emphasis Type="Italic">H</Emphasis>-Pyrrole-2,3-diones. Synthesis of pyrrolo[3,2-<Emphasis Type="Italic">d</Emphasis>]isoxazoles

1H-pyrrol-2,3-diones react with nitrones affording substituted pyrrolо[3,2-d]isoxazoles. The structures of ethyl (3R*,3aR*,6aR*)-6-benzyl-3-(4-bromophenyl)-4,5-dioxo-2,6a-diphenylhexahydro-3aHpyrrolo[ 3,2-d]isoxazole-3a-carboxylate and dimethyl (3R*,3aR*,6aS*)-3-(4-bromophenyl)-4,5-dioxo-2,6-diphenyltetrahydro-3aH-pyrrolo[3,2-d]isoxazole-3a,6a(4H)-dicarboxylate were proved by single-crystal X-ray analysis.     

Pyrrolidine synthons for β-lactams

Fused tricyclic aziridines, methyl rel-(2R,2aR,3R,4R,4aR,4bS)- and rel-(2S,2aR,3R,4R,4aR,4bS)-4-hydroxy-2,4a-dimethoxyhexahydro-1-oxa-2b-azacyclopropa[cd]pentalene-3-carboxylates, have been synthesized as possible precursors to β-lactams. The product structure has been determined by two-dimensional NMR techniques in combination with computational methods.     

Synthesis of Pyrano[4′,3′:2,3]pyrrolo[1,2-<Emphasis Type="Italic">a</Emphasis>]quinoxalines by Reaction of Aroylpyrroloquinoxalines with Alkyl Vinyl Ethers

Thermally induced [4 + 2]-cycloaddition of 3-aroylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones with alkyl vinyl ethers afforded mixtures of diastereoisomeric (5S*,6aR*)- and (5R*,6aR*)-5-alkoxy-3-aryl-5,6-dihydropyrano[ 4′,3′: 2,3]pyrrolo[1,2-a]quinoxaline-1,2,7(8H)-triones.     

New chiral block for cyclopentanoids synthesis

Hydroxymethylation of bicyclic allylsilane, (3aR,6R,6aS)-3,3a,6,6a-tetrahydro-6-(trimethylsilyl)-cyclopenta[c]furan-1-one with formaldehyde by Prins reaction proceeds via S_E2' mechanism with the formation of anti-addition product. Some reactions of obtained (3aS,4S,6aR)-4-(hydroxymethyl)-3,3a,4,6a-tetrahydro-1H-cyclopenta[c]furan-1-one were investigated.     

Reactions of ethyl 6,6-dialkyl-8,9-dioxo-5,6,8,9-tetrahydrobenzo[<Emphasis Type="Italic">f</Emphasis>]pyrrolo[2,1-<Emphasis Type="Italic">a</Emphasis>]isoquinoline-10-carboxylates with <Emphasis Type="Italic">N</Emphasis>-nucleophiles

Reaction of enaminoesters, derivatives of 2,2-dialkyl-1,2,3,4-tetrahydrobenzo[f]isoquinoline, with oxalyl chloride leads to the formation of ethyl 6,6-dialkyl-8,9-dioxo-5,6,8,9-tetrahydrobenzo[f]pyrrolo[2,1-a]-isoquinoline-10-carboxylates. At reaction of the latter with ammonia and cyclic amines opening of pyrroledione cycle occurs and the formation of enaminoketoamides, and the reaction with o-phenylenediamine furnishes a fragment of benzimidazole. Hydroxylamine behaves as binucleophile and attacks not only lactam, but also the ester group, affording heterocyclic system of isoxazine-3,4,6-trione.     

Dehydrogenation of 1-aryl(hetaryl)-1,2,3,4-tetrahydro-9<Emphasis Type="Italic">H</Emphasis>-β-carboline-3-carboxylic acids and their esters with dimethyl sulfoxide

Oxidative dehydrogenation of 1-aryl(hetaryl)-1,2,3,4-tetrahydro-9Н-β-carboline-3-carboxylic acids derivatives with dimethyl sulfoxide leads to the formation of 1-aryl(hetaryl)-9Н-β-carbolines. Simultaneously with the dehydrogenation decarboxylation occurs. At the oxidation with dimethyl sulfoxide of methyl 1-aryl (hetaryl)-1,2,3,4-tetrahydro-9Н-β-carboline-3-carboxylicates methyl 1-aryl(hetaryl)-9Н-β-carboline-3-carboxylates formed whose hydrolysis afforded the corresponding 1-aryl(hetaryl)-9Н-β-carboline-3-carboxylic acids.     

Synthesis of New 1,2,3,4-Tetrahydroisoquinoline Derivatives. 2-(2,3,3-Trimethyl-1,2,3,4-tetrahydroisoquinolin-1-yl)anilines

A four-step procedure has been developed for the synthesis of new 2-(2,3,3-trimethyl-1,2,3,4-tetrahydroisoquinolin-1-yl)anilines by acylation of 2-(3,3-dimethyl-3,4-dihydroisoquinolin-1-yl)anilines at the amino group with isobutyryl chloride, reduction of the endocyclic C=N bond in N-[2-(3,3-dimethyl-3,4-dihydroisoquinolin-1-yl)phenyl]isobutyramides, N-alkylation of N-[2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-yl)phenyl]isobutyramides to N-[2-(2,3,3-trimethyl-1,2,3,4-tetrahydroisoquinolin-1-yl)phenyl]isobutyramides, and acid hydrolysis of the latter.     

Synthesis and structure investigation of Co(III) complex salts with the perrhenate anion

Complex salts of the composition [Co(NH₃)₆](ReO₄)₃·2H₂O (I), [Co(en)₃](ReO₄)₃ (II), [Co(NH₃)₅H₂O](ReO₄)₃·2H₂O (III), and [Co(NH₃)₅Cl](ReO₄)₂·0.5H₂O (IV) are obtained. Their crystal structures are determined by single crystal XRD. Crystallographic characteristics: (I) a = 9.9797(3) Å, b = 12.6994(3) Å, c = 14.7415(4) Å, β = 102.870(1)°, C2/c space group; (II) a = 8.0615(3) Å, b = 8.4483(4) Å c = 8.8267(4) Å, α = 61.923(2)°, β = 89.552(2)°, γ = 72.295(2)°, P1 space group; (III) a = 8.0086(4) Å, b = 12.9839(6) Å, c = 17.5122(7) Å, β=91.858(1)°, P2₁/n space group; (IV) a = 14.9446(3) Å, b = 14.6562(4) Å, c = 12.2434(4) Å, Cmc2₁ space group.     

An efficient synthesis of <Emphasis Type="Italic">β</Emphasis>-methoxycarbonyl-<Emphasis Type="Italic">γ</Emphasis>-butyrolactones

β-Methoxycarbonyl-γ-butyrolactones bearing a γ-aromatic substituent were prepared via copper-catalyzed reductive aldol addition/lactonization domino reactions of ketones with α,β-unsaturated dicarboxylate esters and a silane under ambient temperature. The reaction has advantage of using readily available reagents, mild conditions and high efficiency.     

Apparent Molar Volumes of Aqueous Solutions of Magnesium Tetraborate from 283.15 to 363.15 K and 0.1 MPa

Densities for aqueous solutions of magnesium tetraborate MgB₄O₇(aq) at the molalities of (0.00556–0.03341) mol·kg^?1 were measured with an Anton Paar Digital vibrating-tube densimeter at temperature intervals of 5 K from 283.15 to 363.15 K and 0.1 MPa. Apparent molar volumes were obtained based on the experimental density data, and the 3D diagrams of the apparent molar volume (V _? ) of MgB₄O₇(aq) against temperature (T) and molality (m) were plotted. On the basis of the Vogel–Tamman–Fulcher equation, the coefficients of the correlation equation for densities of MgB₄O₇(aq) against temperature and molality were parameterized. According to the Pitzer ion-interaction model of the apparent molar volume, the temperature correlation equations of Pitzer single-salt parameters F(i,p,T)?=?a₀?+?a₁?×?T?+?a₂?×?T ²?+?a₃/T?+?a₄?×?ln(T)?+?a₅?×?T ³ (where T is temperature in Kelvin, a _i are model parameters) for MgB₄O₇ were obtained for the first time.