Chemical transformations of 3-aminopyrrolidin-2-ones of the norbornane and cyclopropane series

3-Aminopyrrolidin-2-ones containing a fused norbornane or spirocyclopropane fragment react with benzaldehyde to give azomethines, which can be transformed into N-substituted 3-aminopyrrolidin-2-ones by reduction with sodium borohydride. Diazotization of amino-pyrrolidinones with NaNO₂ in acetic acid results in the elimination of molecular nitrogen and in the formation of acetoxy or unsaturated derivatives (through stabilization of intermediate carbocations). 6-Methylidene4-azaspiro[2.4]heptan-5-one obtained by diazotization of 6-amino-6-methyl-4-azaspiro[2.4]heptan-5-one easily reacts with diazomethane, diazocyclo-propane, and benzonitrile oxide to yield heterocyclic spiranes by means of 1,3-dipolar cycloaddition.     

On a question of A. E. Nussbaum on measurability of families of closed linear operators in a Hilbert space

The purpose of this note is to answer a question A. E. Nussbaum formulated in 1964 about the possible equivalence between weak measurability of a family of densely defined, closed operators {T(t)} _t∈ℝ in a separable complex Hilbert space H\mathcal{H} on one hand, and the notion of measurability of the 2 × 2 operator-valued matrix of projections {(P(Γ(T(t))) _j,k )_1⩽j,k⩽2} _t∈ℝ onto the graph Γ(T(t)) of T(t) on the other, in the negative.     

Studying the dimerization reaction during the abstraction of halogen from organohalides by laser photoemission, controlled-potential electrolysis, and voltammetry

To continue earlier investigations into the dimerization reaction during the cathodic cleavage of a carbon-halogen bond and, in particular, to find an accessible way for synthesizing 1,4-butanediol, a comparative study of the dimerization of ethylene halohydrins and butyl and allyl halides is performed. On the basis of the data obtained by the laser photoemission (LPE), controlled-potential electrolysis, and voltammetry techniques, a general mechanism of the electrode reactions involving these compounds and their intermediates is proposed and recommendations on the optimization of the 1,4-butanediol synthesis are elaborated. According to LPE data, at pH < 8.1, the Β-hydroxyethyl radical reduction occurs with a preceding formation of a complex with a proton donor, whereas a direct electron transfer is characteristic of the butyl radical. This difference in mechanisms is offered as the main reason for the lesser capability of ethylene halohydrins to electrochemical dimerization as compared with butyl halides, where the octane yield reached up to 80–84%. The earlier assumption about a high electrocatalytic activity of the copper cathode in dimerization of ethylene halohydrins is confirmed, and possibilities of an iron cathode in this process are revealed. The dimer yield is found to increase in alkaline solutions and at lowered temperatures, specifically, at pH 11 and temperatures of 0–5°C., the 1,4-butanediol yield reached ∼17%.     

Different reactivities of regioisomeric azimines, adducts of phthalimidonitrene with 5-bromospiro[1-pyrazoline-3,1′-cyclopropane]

The addition of the phthalimidonitrene fragment, resulting from oxidation ofN-aminophthalimide by lead tetraacetate at −20 to −30°C, to the N=N-bond of 5-bromospirol[l-pyrazolinio-3,1′-cyclopropane] (1) affords, apart from the stable 5-bromo-N {spiro[l-pyrazolinio-3,1′-cyclopropane]}-N-phthalimidoamide (azimine2), regioisomeric azimine3, which is completely transformed into 3-acetoxy-N-{spiro[l-pyrazolinio-5,1′-cyclopropane]}-N-phthalimidoamide (4) under the reaction conditions. The acetoxy group in this product easily undergoes nuclcophilic substitution on treatment with McOH, NaN₃, or the starting bromopyrazoline1. The structures of azimines obtained were established using NMR spectra, and the structure of the product of reaction of4 with1 was additionally proved by X-ray difraction data. Published inIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 1949–1953, November, 2000.     

Generation of diazo-2-methylenecyclopropane and its 1,3-dipolar cycloaddition to acrylates

N-(2-Methylenecyclopropyl)-N-nitrosourea (2) was synthesized for the first time (yield 70%) and its decomposition induced by bases was studied. In particular, treatment with MeONa/MeOH at-30°C in the presence of methyl methacrylate gives the corresponding I-pyrazoline stereoisomers, the products of [3+2]-cycloaddition of diazo-2-methylene-cyclopropane (1) generatedin situ. Decomposition of2 on treatment with K₂CO₃ at 0–5°C in the presence of acrylonitrile also proceeds as [3+2]-cycloaddition: however, the expected 2-pyrazoline easily isomerizes into 5(3)-isopropenyl-3(5)-cyanopyrazole. Buta1,2,3-triene is the main product of base-induced decomosition of2 in the absence of unsaturated substrates. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1210–1214, July, 2000.     

Reaction of diazoalkanes with unsaturated compounds

A THF solution of diazopropyne was obtained in 60% yield by the reaction of a 30% aqueous solution of methylamine withN,N′-dinitroso-N,N′-dipropargylterephthalodiamide. The reactions of diazopropyne with methyl acrylate and methyl methacrylate giving various ethynylpyrazolines as well as its CuCl-catalyzed decomposition in the presence of norbornene or norbornadiene yielding ethynylcyclopropanes were studied. The main products of catalytic deazotization of diazopropyne in the absence of unsaturated compounds are isomericE- andZ-hex-3-ene-1,5-diynes resulting from propargylene dimerization. For Part 12, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2278–2282, November, 1998.     

Electrochemically induced processes in the formation of phosphorus acid derivatives. 1. Synthesis of trialkyl phosphates from white phosphorus

An electrochemical method, based on the joint action of nucleophilic and electrophilic reagents on P₄, is proposed in order to utilize white phosphorus in the formation of the esters of phosphorus acids. The action of alkoxide ions on white phosphorus in an alcohol medium in the presence of iodine generated at the anode leads to the formation of phosphate esters. A scheme in which the intermediate products are dialkyl and trialkyl phosphites and the side product is dialkyl alkylphosphonate is proposed for the process.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420028 Kazan'. V. I. Ul'yanov-Lenin Kazan State University, 420028 Kazan'. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1322–1328, June, 1992.     

1,3-Dipolar cycloaddition of diazocyclopropane to strained cycloalkenes and conjugated dienes to give spiro(1-pyrazoline-3,1′-cyclopropanes)

Polycyclic spiro(1-pyrazoline-3,1-cyclopropanes) were obtained in 32–70 % yields by the reaction of diazocyclopropane generatedin situ with 2-methyltricyclo[3.2.1.0^2,4]oct-6-ene, spiro[2,4]hepta-4,6-diene dimer, benzvalene, spiro[2,3]hex-1-ene, methyl 1-methylcyclopropene-3-carboxylate, buta-1,3-diene, and 2-methylbuta-1,3-diene.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2199–2202, November, 1995.This study was financially supported by the Russian Foundation for Basic Research (Grant No. 94-03-08902).