The reaction of Tanshinones with Amines

The reaction of cryptotanshinone and tanshinone IIA with several biogenic amine metabolites involved in the pathogenic pathways of HE were investigated and eight 1,2,3,4-tetrahydrophenanthrene derivatives,2-6 and 8-10,were obtained.The probable mechanism on reaction was discussed.     

The reaction of α-stannylmethyllithium with esters

Ketonic compounds were prepared from esters using α-stannylmethyllithium as the reagent.     

The purported reaction of tricarbonyl-η5-cyclohexadienyliumiron tetrafluoroborate with fujoride ion

The product of reaction between tricarbonyl-η⁵-cyclohexadienyliumiron tetrafluoroborate and fluoride ion has been shown to be the diastereomeric ether complex and not the fluorodiene complex as previously reported.     

The interconversion of η5 and η3 hapticities in cycloheptadienyl complexes of molybdenum and tungsten

[Mo(CO)₄(η⁵-C₇H₉)]⁺ (1) reacts with acetonitrile to give [Mo(CO)₂(NCMe)₃(η³-C₇H₉)]⁺ (3), which is precursor of a wide reange of η⁵-cycloheptadienyl complexes [Mo(CO)₂L₂(η⁵-C₇H₉)]⁺ [6, L = PPH₃; 7, L₂ = Ph₂PCH₂PPh₂; 8, L₂ = 1,3-cyclohexadiene; 9, L₂ = 2,2′-dipyridyl]; 9 reacts reversibly with NCMe to give [Mo(CO)₂(NCMe)(dipy)(η³-C₇H₉)]⁺ (10).     

Substitution reaction of η5-cyclopentadienylruthenium(II) complexes with nitrogen,oxygen and sulfur donor ligands

The heterocycles pyridine, γ-picoline, 2,2′-bipyridine and 1,10-phenanthroline react with [(η⁵-C₅H₅)Ru(MPh₃)₂X] (M = P, As or Sb) and [(η⁵-C₅H₅)Ru(AsPh₃)(PPh₃)X] (X = Cl, Br, I, CN, NCS or SnCl₃) to form complexes of types [(η⁵-C₅H₅)(MPh₃)(L−L)⁺X⁻ (L−L = 2,2′−bipyridine or 1,10−phenanthroline; X = Cl, Br, I, CN, NCS or SnCl₃) and [(η⁵-C₅H₅)Ru(MPh₃)LX] (M = As or Sb; L = pyridine or γ-picoline; X = Cl, Br, I, CN, NCS or SnCl₃). Interactions of dithiocarbamate (DTC) with [(η⁵-C₅H₅)Ru(SbPh₃)₂X] (X = Cl, Br or I) and acetylacetonate (acac) with parent compounds [(η⁵-C₅H₅)Ru(MPh₃)₂X (M = P or Sb; X = Cl, Br or I) yielded [(η⁵-C₅H₅)Ru(MPh₃)L] (where L = DTC or acac). The reaction products have been characterized by magnetic, spectral and microanalytical data.     

The reaction of 2,5-diphenylphosphacymantrene with solid KOH in the presence of crown ethers: Synthesis of the anionic η-phosphoryl manganese complexes

2,5-Diphenylphosphacymantrene (1) reacts with solid KOH in the presence of crown ethers in C₆H₆ or CH₂Cl₂ at room temperature adding OH nucleophile to the phosphorus atom to afford anionic complexes [(CO)₃Mn-η⁴-2,5-Ph₂H₂C₄P(O)H]⁻ [K−Crown]⁺, where Crown = 18-crown-6 (2) or dicyclohexyl-18-crown-6 (3). Complexes 2 and 3 are characterized by ¹H, ³¹P, ¹³C NMR and IR-spectra. The structure of 2 is established by X-ray crystal structure data.     

The reaction of carbohydrates and uronic acids with β-methylindole

Aldo- and ketu-hexoses produce with β-methylindole a pigment that is soluble with blue color in chloroform. The same applies to ω-hydroxymethylfurfural. Pentoses and uronic acids as well as furfural produce an olive color reaction, but no blue Soluble pigment. Methylpentoses and methylfurfural produce a red pigment, the chloroform extract of which is of raspberry color. The behavior of the heptoses is not characteristic. There is no possibility of differentiating between glucurone and galacturonic acid.     

The reaction of benzothiazolyl substituted α-phosphorylmethyl sulfoxides with several amines

We have examined the reactivities of α-phosphorylmethyl benzothiazolyl sulfoxides in the thermolyses and in the presence of several amines, such as aniline, benzylamine, piperidine, morpholine, and pyrrolidine. Thermolyses of the derivatives in the presence of 2,3-dimethyl-1,3-butadiene afforded 2-phosphoryl substituted 4,5-dimethyl-3,6-dihydro-2H-thiopyran S-oxide. In the reaction with amines, the complex product mixture, which contains α-phosphorylmethyl benzothiazolyl sulfides (2 and 5), α-phosphorylmethyl disulfides (15 and 16), and 2-amino substituted benzothiazole 14 was found to be formed besides the target phosphinecarbothioamides. Several mechanistic studies were performed to elucidate the formation mechanism, particularly for deoxygenated products from the starting sulfoxides, i.e., 2 and 5 from 3 and 6, respectively.     

Oxidation of isomeric η6- and η5-fluorenylchromiumtricarbonyl anions

The oxidation of the carbon-centered [(⁶-C₁₃H₉)Cr(CO)₃]^– anion (1 ^–) results in formation of (-⁶:⁶-9,9-bifluorenyl)bis-chromiumtricarbonyl (3) due to coupling of the intermediate carbon-centered radical (1^.). The oxidation of the metal-centered anion [(⁵-C₁₃H₉)Cr(CO)₃]^– (2 ^–), which is isomeric to the 1^– anion, gives an equilibrium mixture of the chromium-centered radical {(⁵-C₁₃H₉)Cr(CO)₃}^. (2 ^.) and its dimer [(⁵-C₁₃H₉)Cr(CO)₃]₂ (6). Radical2 ^. readily reacts with MeI and the solvent (THF); the resulting derivatives, (⁵-C₁₃H₉)Cr(CO)₃R (R=Me (10); R=H (7)), undergo fast ricochet inter-ring ⁵⁶ rearrangements into (⁶-9R-C₁₃H₉)Cr(CO)₃ (R=CH₃ (9); R=H (4)).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1354–1358, July, 1995.The authors are grateful to D. V. Zagorevskii who recorded the mass spectra. This study was financially supported by the Russian Foundation for Basic Research (Grant No. 94-03-05209) and the International Science Foundation (Grant Nos. MQ 4000 and REV 000).     

The condensation reaction of methylphosphonic acid with α,ω-diethoxydimethylsiloxanes

Russian Chemical Bulletin -     

Redox-induced η5 ⇔ η3 haptotropy of the fluorenyl ligand in 9-substituted η5-fluorenylmanganesetricarbonyl complexes

It has been shown by cyclic voltammetry in THF within the –90 to 40 °C temperature range that fluorenyl (⁵-9-R-C₁₃H₈)Mn(CO)₃ complexes (R=Bu^t (3) and Ph (4)) undergo two-electron reduction to form allyl type [(³-9-R-C₁₃H₈)Mn(CO)₃]^2– dianions as final products. At low temperatures complexes3 and4 are reduced in two one-electron steps according to the EEC-scheme. The first step is reversible and corresponds to the formation of 19-radical anions 3^–. and 4^–.. TheE ⁰ values for redox pairs3 ^0/–. and4 ^0/–. are –1.88 and –1.73 V, respectively. The further reduction of radical anions3 ^–. and4 ^–. at more negative potentials is accompanied by fast ^{5 3} haptocoordination of the fluorenyl ligand to form 18-dianions [(³-9-R-C₁₃H₈)Mn(CO)₃]^2–. These dianions obtained by the reduction of complexes3 and4 by the radical anion of pyrene are stable at –80 °C and are characterized by their IR spectra. At room temperature the ^{5 3} hapticity change is a fast and reversible process occurring at the step of 19-radical anions3 ^–. and4 ^–. and leading to the electron deficient 17-species [(³-9-R-C₁₃H₈)Mn(CO)₃]^–., which are reduced easier than the initial complexes. As a result, complexes3 and4 are reduced to the corresponding dianions [(³-9-R-C₁₃H₈)Mn(CO)₃]^2– at room temperature in one reversible two-electron step according to the ECE-scheme. Reactivities of 19e^–-species of the isomeric ⁵- and ⁶-fluorenylmanganesetricarbonyl complexes are compared.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1347–1353, July, 1995.The work was financially supported by the Russian Foundation for Basic Research (Project No. 93-03-05209) and the International Science Foundation (Grant No. REV 000).     

The reaction of trifluoromethanesulfenyl chloride with enamines of β-keto carboxylic acid anilides

1-Morpholino-cyclopenten-2-carboxylic acid anilides react with CF₃SCl in molar ratio 1:2 to give products of the displacement of two hydrogen atoms at C-2 and C-5. The analogous reaction with enamines of cyclohexanono- and cycloheptanono- 2-carboxylic acid anilides and benzoylacetanilides proceeds in 1:1 molar ratios affording enamines and keto compounds.     

Ortho-metallation of η-pyrrolylmetal complexes with triosmium clusters

The cluster [O₃(CO)₁₀(MeCN)₂] reacts with (η-cyclopentadienyl)(η-pyrrolyl)iron [azaferrocene, Fe(C₅H₅)(C₄H₄N) under mild conditions to give the oxidative addition product [Os₃H{(C₄H₃N)Fe(C₅H₅)}(CO)₁₀]. The group (C₄H₃N)Fe(C₅H₅) acts as a three-electron donor through the ortho-metallated pyrrolyl ring. An analogous compounds, [Os₃H{(C₄H₃N)Mn(CO)₃}(CO)₁₀], is obtained by the reaction of [Os₃(CO)₁₀(MeCN)₂] with [Mn(η-pyrrolyl)(CO)₃].     

Hydroxylation of azomethine carbon: isolation of complexes of η5 and η6-cyclic hydrocarbon platinum group metals with a new Schiff-base ligand

A new Schiff base, (pyridin-2-yl)-N-(3,5-di(pyridin-2-yl)-4H-1,2,4-triazol-4-yl)methanimine, (L), was synthesized. Reaction of [(η⁶-arene)Ru(µ-Cl)Cl]₂ and [Cp*M(µ-Cl)Cl]₂ (M = Rh and Ir) with one equivalent of L in the presence of NH₄PF₆ in methanol yielded dinuclear complexes, [(η⁶-arene)₂Ru₂(L-OH)Cl](PF₆)₂ {arene = C₆H₆ (1), p-ⁱPrC₆H₄Me (p-cymene) (2) and C₆Me₆ (3)}, and [Cp*₂M₂(L-OH)Cl](PF₆)₂ [M = Rh (4) and Ir (5)], respectively, leading to the formation of five new chiral complexes with –OH on the azomethine carbon. L is a pentadentate ligand where one of the metal centers is coordinated to two nitrogen atoms in a bidentate chelating fashion while the other metal is bonded tridentate to three nitrogen atoms. Although the ligand is neutral before coordination, after complexation it is anionic (uni-negative) with negative charge on the azo nitrogen {see the structures: N(5) in 2[PF₆]₂ and N(3) for 4[PF₆]₂}. The complexes have been characterized by various spectroscopic methods including infrared and ¹H NMR and the molecular structures of the representative complexes are established by single-crystal X-ray diffraction studies.     

The reaction of cyclopentyne with ethene: concerted vs stepwise mechanism?

The cycloaddition of cyclopentyne with ethene was examined using (U)B3LYP and CASSCF methods to discern the reaction mechanism. (U)B3LYP/6-31G* and (U)B3LYP/6-311+G* slightly favor the concerted pathway, whereas CASSCF(4,4)/6-31G* and CASCF(6,6)/6-31G* favor the diradical pathway. MRMP2 using the CASSCF(4,4) wave function also favors the diradical mechanism. In the context of a diradical pathway, the experimentally observed complete retention of stereochemistry for this reaction is understood in terms of stereochemical control resulting from dynamic effects.     

The reaction of carbohydrate-derived alkoxyaldehydes with methoxycarbonylmethylenetriphenylphosphorane: stereoselective synthesis of β-unsaturated esters

The reaction of several carbohydrate-derive alkoxyaldehydes with methoxycarbonylmethylenetriphenylphosphorane afford α, β-unsaturated esters with Z-stereoselectivity. The stereoselectivity depends on the substrate stucture and the nature of the solvent used.     

Acetylation and benzoylation of η5,η5-fulvalenedimanganesehexacarbonyl

⁵,⁵-Fulvalenedimanganesehexacarbonyl (dicymantrenyl) was acetylated and benzoylated by RC(O)Cl+AlCl₃ in CH₂Cl₂, under conditions of the Friedel-Crafts reaction. The reaction involves both nonequivalent positions of the cyclopentadienyl rings to give mixtures of two isomeric ketones. When using an excess of the acetylating mixture, diacetyl derivatives of dicymantrenyl were obtained.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2017–2020, October, 1995.The authors are grateful to P. V. Petrovsky and E. V. Vorontsov (the NMR laboratory of the Institute of Organoelement Compounds, Russian Academy of Sciences) for recording¹H NMR spectra.