Synthesis of 2-keto-4-phosphorylbutyric acids and their derivatives

The Claisen condensation of 3-phosphorylated propionitriles with diethyl oxalate has been examined. The product of the condensation of 3-(methylethoxyphosphinyl)propionitrile, following hydrolysis, has been shown to be the enol form (Z-isomer) of 4-(methylhydroxyphosphinyl)-3-cyano-2-ketoburyric acid. On crystallization from water, the other isomers (the E-isomer of the enol or the keto-forms) were not isolated. Distillation of the products of silylation of the reaction mixture with hexamethyldisilazane gave both geometric isomers of the enol (Z and E). In aqueous solution, the enol gradually cyclizes to give 2-hydroxy-3-(methylhydroxyphosphinyl)citraconimide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2120–2127, September, 1990.     

On the possibility of a carbenium ion structure for the complexes [Os3H3(CO)9CCR2]+. Further application of the 187Os nucleus

In the ¹H NMR spectrum of the complex [Os₃H₃(CO)₉C$\text{C(CH}{}_2\text{C}$H₂]⁺ at 30°C, under conditions of rapid exchange, the single hydride resonance has two sets of satellites of equal intensity (separated by 32.0 and 28.8 Hz) caused by ¹⁸⁷Os¹H spin—spin coupling. The spectral data rule out the upright carbenium ion structure for the complex, and are consistent with the fluxional process involving hydrocarbon ligand rotation about the C$\text{C(CH}{}_2\text{)}{}_2\text{C}$H₂ axis in a tilted structure, with concomitant rotation of the Os₃H₃(CO)₉ moiety.     

Coordination chemistry of macrocyclic multidentate Lewis acids. Synthesis and structures of complexes of cyclic trimeric perfluoro-o-phenylenemercury with N,N-dimethylacetamide and n-butyronitrile

Cyclic trimeric perfluoro-o-phenylenemercury (o-C₆F₄Hg)₃ readily reacts with N,N-dimethylacetamide and n-butyronitrile to form the complexes {[(o-C₆F₄Hg)₃](MeCONMe₂)₂} and {[(o-C₆F₄Hg)₃](PrⁿCN)}, respectively. According to X-ray diffraction data, the amide ligands are located above and below the plane of the macrocycle, each being coordinated to all Hg atoms of the macrocycle through the O atom. The nitrile ligand is bound to the macrocycle through the N atom, all Hg atoms being also involved in this bonding.     

Selected properties of bi- and trinuclear complexes prepared by the reactions of Ru3(CO)12 with β-substituted oxadienes

The reactions of Ru₃(CO)₁₂with 4-phenylbut-3-an-2-ine (1a), 3-phenyl-1-p-tolylprop-2-an-1-ine (1b), and 1,3-diferrocenylprop-2-an-1-ine (1c) afforded the Ru₂(CO)₆(-H)(O=C(R¹)C(H)=C(R²)) (2) and Ru₃(CO)₈(O=C(R¹)C(H)=C(R²))₂(3) complexes. Dissolution of these complexes in CHCl₃or CH₂Cl₂gave rise to the Ru₂(CO)₄(-Cl)₂(O=C(R¹)C(H)=C(R²)) complexes (4). The thermal transformations of complexes 2and 3in the presence of an excess of the ligand yielded the Ru₂O₂(CO)₄(³-OC(R¹)C(H)(CH₂R²)C(R²)C(H)C(R¹))₂(5) and Ru(CO)₂(O=C(R¹)C(H)=C(R²))₂(6) complexes. Analogous complexes were obtained upon more prolonged heating of the starting reaction mixtures. The structures of complexes 4a, 5a, and 6cwere established by X-ray diffraction analysis and confirmed by spectroscopic data.     

Novel reactions of arylmalonate carbanions. The reaction with phenyl isocyanate resulting in carbamates by 1,3-C→N migration of the ethoxycarbonyl group

The reactions of carbanions of diethyl phenyl and 4-nitrophenylmalonates with phenyl isocyanate occur with 1,3-C→N migration of the ethoxycarbonyl group to form the corresponding adducts. The introduction of NO₂ groups into the benzene ring of arylmalonates inhibits the reaction. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1608–1610, August, 2007.     

Synthesis and properties of mono- and bis[2-(dimethylaminomethyl)]cymantrenyl derivatives of ytterbium

The reaction of [2-(dimethylaminomethyl)]cymantrenyl]lithium with ytterbium diiodide affords [2-(dimethylaminomethyl)cymantrenyl]ytterbium iodide or bis[2-(dimethylaminomethyl)cymantrenyl]ytterbium depending on the ratio of the starting reactants. Reactions of these complexes with a series of electrophiles (H₂O, Me₃SiCl, MeCOCl, HgCl₂, PhCOCl) were studied and the corresponding derivatives of cymantrene were prepared in high yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No.3, pp. 531–533, March, 1994.     

Intramolecular condensation of nitro group with olefinic double bond

Conclusions A new reaction of nitro compounds was discovered on the example of the thermal isomerization of unsaturated nitrocarbinols and nitrodihydropyrans, consisting in the intramolecular addition of the nitro group to the olefinic double bond with the formation of the heterolytic 1,3,2-dioxazoline system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 370–378, February, 1968.     

Redox reactions involving low-valence transition metal complexes: Palladium and platinum phosphinecarbonyl clusters in the synthesis of binuclear compounds

Conclusions The heterobinuclear complex, PtPdCl₂(₂-CO)(PPh₃)₃ was obtained by the redox addition of Pd₄(CO)₅(PPh₃)₄, and Pt₄(CO)₅(PPh₃)₄, to MCl₂(PPh₃)₂, where M=Pd and Pt, as a single isomer containing the two PPh₃ ligands at the platinum atom.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2360–2362, October, 1987.     

Reactions of 1,4-difeffocenylbuta-1,3-diyne and 1,4-diphenylbut-l-en-3-yne with Ru3(CO)12. Crystal structure of Ru3(CO)8(μ3-η-1-η1-η4-η2-C4Ph2(CH=CHPh)2)

Diyne FcCmCC.CFc (Fc is ferrocenyl) reacts with Ru₃(CO)₁₂ in boiling hexane to yield binuclear complexes Ru₂ and Ru₂(CO)₆(C₄Fc₂(C=CFc)₂C=O) containing ruthenacyclopentadiene and diruthenacycloheptadienone rings, respectively. The isomerism of the complexes is due to the different ways of coupling of the alkyne fragments of the diyne, namely, head-to-head, head-to-tail or tail-to-tail. The reaction of enyne PhC=CCH=CHPh with Ru₃(CO)₁₂ under similar conditions gives isomeric binuclear complexes Ru₂(CO)₆(C₄Ph₂(CH=CHPh)₂) and trinuclear clusters Ru₃(CO)₆(w-CO)₂(C₄Ph₂(CH=CHPh)₂) and Ru₃(CO)₈(₃-,¹-¹-⁴-² C₄Ph₂(CH=CHPh)₂). The structure of the latter was determined by X-ray diffraction analysis. The Ru₃ triangle coordinates eight terminal CO groups and the organic ligand resulting from the head-to-head dimerization of enyne molecules; the ruthenacyclopentadiene moiety is ⁴-coordinated to the Ru(CO)₂ group, and the third ruthenium atom is 2-bound to one of the PhCH=CH groups.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1261–1267, May, 1996.