Synthesis and properties of dicyclopentadienyltantalum(III) carbonyl compounds

Reaction of Cp₂Ta(H)L (L = C₃H₆, C₄H₈, C₅H₁₀ and C₅H₈) with CO under mild conditions gives alkyltantalum carbonyl complexes Cp₂Ta(CO)R (R = C₃H₇, C₄H₉, C₅H₁₁ and C₅H₉, respectively). Depending upon the position of the olefin relative to the hydride ligand in the hydride-olefin complex, Cp₂Ta(CO)H is also formed during the carbonylation reaction. Reduction of Cp₂TaCl₂ by potassium or t-BuMgCl under one atmosphere of CO affords the very stable compound Cp₂Ta(CO)Cl in moderate yields. Reaction of Cp₂Ta(CO)Cl with RLi or RMgX does not give the Cp₂Ta(CO)R complex.     

The structure and properties of carbonyl compounds

The (planar) minimum energy configurations of cis and trans glyoxal, and of parabenzoquinone, have been determined using the MINDO/2 method. Good agreement with the experimental structures is obtained. Other molecular properties for these systems are reported.     

Synthesis of 3-Trifluoromethyl-4-halobenzonitriles

The practical synthetic method for a series of substantially novel fluorine-containing polyfunctional aromatic compounds, 3-trifluoromethyl-4-halobenzonitriles [halo = Cl, Br, and F], was established by using copper-cyano complexes as effective Sandmeyer cyanating reagents.     

Preparation and properties of cyclodextrin-metal carbonyl inclusion compounds

One-to-one inclusion compounds were obtained in a crystalline state in high yields by treatment if ironpentacarbonyl and dimanganesedecacarbonyl with γ-cyclodextrin. These represent the first examples of cyclodextrin inclusion compounds with binary metal carbonyl complexes; the metal carbonyl complexes included in cyclodextrins are thermally more stable than the free complexes.     

1-Amino-2-hydrazinobenzimidazole and its reactions with some carbonyl compounds

1-Amino-2-hydrazinobenzimidazole was obtained for the first time by treating 1-aminobenzimidazole-2-sulfonic acid with hydrazine hydrate. This compound readily condensed with aromatic aldehydes involving both amino groups. The condensation with 2,4-pentanedione affords 1-amino-2-(3,5-dimethylpyrazol-1-yl)benzimidazole, and with α-ketoacids in glacial acetic acid yields mixtures of 10-acetylamino-3-R-1,2,4-triazino[4,3-a]benzimidazol-4(10H)-ones and 4-amino-2-R-1,2,4-triazino[2,3-a]benzimidazol-3(4H)-ones.     

新型2-三氟甲基-4-氨基喹啉衍生物的合成及抗肿瘤活性研究

以4-氟苯胺为起始原料,依次经环合、氯化、偶联、烷基化、还原以及亲核取代反应,设计并合成了10个新型的2-三氟甲基-4-氨基喹啉衍生物(5a~5e、 6、7a~7d),其结构经¹H NMR、 ¹³C NMR、 ¹⁹F NMR及MS（ESI）表征。采用MTT法评价了目标化合物对前列腺癌细胞（PC3、 LNCaP）和慢性髓系白血病细胞（K562）的体外抑制活性。结果表明：在5 μmol·L^-1浓度下,化合物5b、 5c及6对PC3细胞的抑制率,以及化合物7a对K562细胞的抑制率均优于阳性对照药紫杉醇,抑制率分别为50.6%、 52.1%、 54.7%及57.6%。      

Heteroarylthiomethylsilanes. Synthesis and application to heteroarylthiomethylation of carbonyl compounds [1]

Heteroarylthiomethyltrimethylsilanes bearing a 2-pyridyl, 2-imidazolyl, 5-tetrazolyl, or 2-pyrimidinyl group, readily prepared by the reaction of heteroarylmercaptans with halomethyltrimethylsilane in the presence of a base, are synthetic equivalents of heteroarylthiomethyl anions, otherwise inaccessible, and are effective reagents for the introduction of a heteroarythiomethyl group at a carbonyl carbon atom in the presence of a catalytic amount of tetrabutylammonium fluoride.     

2-Trifluoromethyl-4-butanolides

Specific features were elucidated for the intramolecular cyclization of 2-trifluoromethyl-4-pentenoic acids (Ia)-(Ic) under acid catalysis and upon bromination and epoxidation of the double bond. Feasibility was demonstrated for the lactonization of acids (Ia)-(Ic) upon the trifluoroacetoxylation of the double bond and some properties of the butanolide products were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 516–521, February, 1991.     

Synthesis and olefination of carbonyl compounds using solid-supported reagents

The development and application of three new solid-supported reagents for use in the synthesis or olefination of carbonyl compounds are described. The reagents include the Weinreb amide, Mukaiyama's S-2-pyridyl thioate and a Peterson methylenation reagent. As solid-supports p-benzyl alcohol resin, Wang resin and Merrifield resin (1-2% crosslinked polystyrene) have been used.     

Synthesis of cyclic acetals of acetylenic carbonyl compounds

A condensation of α-acetylenic carbonyl compounds and their acyclic acetals with 1,2-diols gave substituted 1,3-dioxacycloalkanes in up to 90% yields. 2,4-Disubstituted 1,3-dioxolanes were formed as mixtures of steric isomers, in which trans-forms predominated according to the B3LYP/6-311+G(2d,p) calculations.     

Synthesis and structures of substituted tetramethylcyclopentadienyl dinuclear metal carbonyl compounds

Cyclopentadienes (C₅Me₄R) [R = Allyl (1), n-Butyl (2), Benzyl (3), and PhMe-2 (4)] reacted with Fe(CO)₅ in refluxing xylene to give new substituted tetramethylcyclopentadienyl dinuclear iron carbonyl complexes [(η ⁵-C₅Me₄R)Fe(CO)(μ-CO)]₂ [R = Allyl (5), n-Butyl (6), Benzyl (7), and PhMe-2 (8)], respectively. The four new complexes 5–8 were characterized by elemental analysis, IR, and ¹H NMR spectra. The crystal structures of complexes 5–7 were determined using single crystal X-ray diffraction. The crystal structure of complex 5 showed that allyl underwent isomerization to give the corresponding methyl-vinyl. A possible mechanism is discussed. The X-ray crystal structures of complexes 5, 6, and 7 confirm the structure with bridging and terminal CO groups. They show that the steric effects of substituents influence the Fe–Fe bond distances of the complexes.     

Synthesis and properties of 2-azahetarylaminomethylidene 1,3-dicarbonyl compounds

Reactions of 2-ethoxymethylidene 1,3-dicarbonyl compounds with pyridine-2,6- and pyrimidine-4,5-diamines gave the corresponding 2-hetarylaminomethylidene derivatives. Depending on the initial reactant structure, the formation of mono-and/or bis-condensation products is possible. Hetarylaminomethylidene derivatives showed a moderate tuberculostatic effect. 2-Pyridinylaminomethylidene 3-oxo esters were used as ligands to obtain coordination compounds with d- and f-metal ions.     

2-Trifluoromethyl-1,1,1,2,6,6,7,7,7-nonafluoro-3,4,5-heptatrione

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1941–1942, August, 1991.     

Synthesis and properties of macroheterocyclic compounds containing 1-imino-2-phenyl-1H-inden-3-amine fragments

Reaction of 1-imino-2-phenyl-1H-inden-3-amine with 3,3′-dichloro-, 2,2′-disulfo-, and 2,2′-dinitrobiphenyl-4,4′-diamines gave 2 : 1 and 1 : 2 linear condensation products and symmetrical macroheterocycles. The products were characterized by the IR, UV, and 1H NMR data.