Reactions of alkyl (halomethyl)furancarboxylates with hexamethylenetetramine

All isomers of (aminomethyl)furancarboxylic acids were prepared by the Delepine reaction from alkyl (halomethyl)furancarboxylates. Treatment of the initially formed quaternary salt with an ethanolic HCl solution yielded the salts of the corresponding unstable amino acid esters. A procedure for their purification to a high degree of purity was developed. Hydrolysis of the crude esters yielded stable amino acid salts.     

Energy of a Relativistic Fermion in a Spherically Symmetric Potential Well of Finite Depth Near the Boundary of the Lower Continuum in a Two-Dimensional Space

Russian Physics Journal -     

Heterocyclic nitro compounds

Reaction of 1-methyl-3, 5-dinitro-1, 2, 4-triazole with aliphatic amines results in the replacement of the nitro group in the 5-position of the triazole ring by the amino group. Some reactions of the compounds obtained have been investigated.For part II, see [1].     

A generating function for Rankin–Cohen brackets

We give a closed formula for the Rankin–Cohen formal covariant quantization in terms of generating functions of Jacobi polynomials.     

Private Life of GL(5,ℤ)

In the paper, the (2, 3)-generation of GL(S, ℤ) is investigated. We reduce the problem to five specific pairs of matrices. Bibliography: 4 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 305, 2003, pp. 153–162.     

Differential symmetry breaking operators: I. General theory and F-method

We prove a one-to-one correspondence between differential symmetry breaking operators for equivariant vector bundles over two homogeneous spaces and certain homomorphisms for representations of two Lie algebras, in connection with branching problems of the restriction of representations. We develop a new method (F-method) based on the algebraic Fourier transform for generalized Verma modules, which characterizes differential symmetry breaking operators by means of certain systems of partial differential equations. In contrast to the setting of real flag varieties, continuous symmetry breaking operators of Hermitian symmetric spaces are proved to be differential operators in the holomorphic setting. In this case, symmetry breaking operators are characterized by differential equations of second order via the F-method.     

Synthesis and Phosphorylation of 2- and 3-Halomethyl Derivatives of Functionalized 2-tert-Butylfurans

2-Halomethyl derivatives of 3-functionalized 5-tert-butylfurans are phosphorylated underconditions of the Michaelis-Becker, Arbuzov reactions similarly to other halomethylfurans. No effectof the tert-butyl substituent on the yield of the reaction products was found in this case. Contrary to that, the2-methoxymethyl derivative of 3-chloromethyl-5-tert-butylfuran proved to be more thermostable than its analog containing no tert-butyl substituent. As a result, the yield of phosphonate in the Michaelis-Becker reaction under similar conditions increases 2.5 times. The observed stabilization of the furan ring is explained by shielding of its oxygen atom by the tert-butyl group.     

Adamantylazoles. Acid-catalyzed adamantylation of 1,2,4-triazoles

The reaction of 1-adamantanol with 1,2,4-triazole in sulfuric acid forms 1-adamantyl derivatives. In boiling chloroform containing traces of sulfuric acid, a mixture of isomeric N-adamantyl-1, 2, 4-triazoles is obtained. It is shown that 1-adamantyl carbocation is formed at a sulfuric acid concentration above 70%.St. Petersburg State Technological Institute, St. Petersburg 198013. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsklicheskii Soedinenii, No. 8, pp. 1078–1087, August, 1996. Original article submitted June 7, 1996.     

Diazotization of aminonitropyrazoles

3(5)-Diazonia-4-nitropyrazole hydrochloride, which readily undergoes nucleophilic substitution, is formed by diazotization of 3(5)-amino-4-nitropyrazole. Depending on the conditions, in the diazotization of 3,5-diamino-4-nitropyrazole one or both amino groups undergo reaction. Moreover, a nitro group is simultaneously replaced by a hydroxyl group, and the final product is 3,5-bisdiazo-4-pyrazolone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1649–1653, December, 1976.     

Furoyl phosphonates

A series of furoyl phosphonates bearing methyl, methoxymethyl, and diethoxyphosphorylmethyl groups in the furan ring have been synthesized via the Arbuzov reaction from the corresponding acid chlorides. NMR spectral parameters of the prepared compounds were studied. The values of coupling constants between the phosphorus nuclei and the carbon nuclei of the furan ring have been examined with relation to the location of the acylphosphoryl group in the furan ring, the nature of second substituent, and location of the latter with respect to the phosphorus-containing substituent in the furan ring. The substitution in position 4 of the furan ring of 3-furoyl phosphonates has been shown to strongly decrease the value of the coupling constant between the phosphorus nucleus and the C² atom of the heterocycle. The interaction between the phosphorus nuclei has not been detected in the spectra of the compounds containing both diethoxyphosphorylmethyl and acylphosphonate fragments.