First example of the formation of bipolar spiro σ-complexes from 6-bromo-5,7-dinitrobenzo[e]-1,2,3,4-tetrazine 1,3-di-N-oxide

The reactions of 3,5,7-trimethyltropolone and 2-(N-benzylamino)tropone with 6-bromo-5,7-dinitrobenzo[e]-1,2,3,4-tetrazine 1,3-di-N-oxide afforded novel bipolar spiro -complexes. The kinetic and activation parameters of the R,S-enantiotopomerization of a chiral spiro -complex of 2-(N-benzylamino)tropone were determined using dynamic ¹H NMR spectroscopy.     

Calculating a function of a matrix with a real spectrum

Let T be a square matrix with a real spectrum, and let f be an analytic function. The problem of the approximate calculation of f(T) is discussed. Applying the Schur triangular decomposition and the reordering, one can assume that T is triangular and its diagonal entries t_ii are arranged in increasing order. To avoid calculations using the differences t_ii ? t_jj with close (including equal) t_ii and t_jj, it is proposed to represent T in a block form and calculate the two main block diagonals using interpolating polynomials. The rest of the f(T) entries can be calculated using the Parlett recurrence algorithm. It is also proposed to perform some scalar operations (such as the building of interpolating polynomials) with an enlarged number of significant decimal digits.

     

The kinetic use of stable nitroxyl radicals in reactions of phosphites

Conclusions It was shown by the method of radical acceptors-stable nitroxyl radicals-that phosphoranyl radicals, formed in the reaction of tert-butylhydroperoxide with triethyl phosphite, are converted to phosphoranyl peroxide radicals in the presence of oxygen. The rate constant of formation of phosphoranyl peroxide radicals found at 20° is 250 times lower than the rate constant of the disproportionation of primary phosphoranyl radicals according to the reaction with the free radical.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2454–2458, November, 1973.     

Extraction recovery of vanadium(V) from sulfuric acid solutions

The IR and electronic absorption spectra of di-2-ethylhexyl hydrogen phosphate (HDEHP) extracts of vanadium(V) and sulfuric acid and of vanadium(V) solutions in sulfuric acid were studied. The composition of the extractable complex was determined, and the equation of vanadium(V) extraction with HDEHP was suggested. The equilibrium constant of vanadium(V) extraction from concentrated sulfuric acid solutions was found.     

Intramolecular π-complexes based on nitroaryl derivatives of furotroponimine: structure and stereodynamics

Neutral aromatic electrophiles, such as trinitrobenzene and dinitrobenzofuroxane, covalently bound to the furotroponimine moiety form intramolecular through-space charge-transfer π-complexes both in solution and in the crystalline state. The kinetic and activation parameters of stereodynamic processes were determined by dynamic NMR spectroscopy. These parameters provide quantitative estimates of the kinetic stability of the p-complexes. The electronic and geometric characteristics of the π-complexes were calculated by the B3LYP/6-31G** method.     

New method of synthesis of β,β′-spiropyrrolidinooxindoles

Russian Journal of Organic Chemistry -     

Synthesis of Phenanthrene Alkaloids from Herbal Aporphine Alkaloids in Subcritical Water Using Synthesis of Seco-Glaucine as an Example

Transformation of the model aporphine alkaloid glaucine into the phenanthrene alkaloid secoglaucine (seco-GL) in subcritical water at 100–250°C without catalytic additives is studied. The maximum yield of seco-glaucine is achieved at 250°C. It is shown that under these conditions the load of the initial compound affects only slightly the yield of the target compound, which is on average 80%. The increase of the GL load up to 400 mg results in precipitation of the target seco-GL directly from the reaction mixture. The suggested method avoids the use of costly and toxic organic solvents.