Autoassembling of cage structures

Treatment of alkylenebismalonates with NaH and benzoyl peroxide afforded dibenzoyloxy derivatives. Alkaline hydrolysis of the latter gave alkylenebistartronic acids. Tetramethyl and tetraethyl esters and tetraamides of these acids were synthesizedFor Part 7, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2190–2193, December, 1994.This study was financially supported by the International Science Foundation (Grant MCO 000), NATO (LG 921193), and the Russian Foundation for Basic Research (Project No. 94-03-08730).     

Self-assembly of frame structures. 10. Stereochemistry of 2,5-dioxabicyclo [2.2.1]heptane-3,6-digne

By optimization of the geometry of 2, 5-dioxabicyclo[2. 2.1]heptane-3.6-dione (1) with an ab initio (RHF/6-31 G') calculation, we have found that a single synchro(+, +)-twist form (A) corresponds to the (1 R,4R)-enantiomer (the dihedral angles of the lactone bridges are ₀ = 2.6°). According to MM2(91) and MM3(92) calculations, (1R,4R)-1 exists as the s-ynchro(+, +)-A-twist ( ₀ = 3.9°) and the synchro(-, -)-B-twist ( = -3.8°) forms, respectively. Investigating the torsional energy surface of the dilactone 1 (MM2(91)), we found only the (1R,4R,P)-diastereomeric form (A), which is stabilized compared with the (1R,4P,M) form (B) (probably as a result of the more preferred dipole-dipole interaction of the carbonyl groups). According to the calculated puckering coordinates, the five-membered and six-membered moieties of the bicycle 1 are flattened compared with norbornane.Institute of Chemical Physics at Chernogolovka. Russian Academy of Sciences, Chernogolovka, Moscow Oblast 142432. Department of Chemistry, University of Calgary, Alberta, Canada T2N 1N4. Department of Chemistry, College of Sciences, Autonomous University of Barcelona, Bellaterra 08193, Spain. Laboratory of Organic Chemistry, College of Pharmacy, University of Barcelona, Barcelona 08028, Spain. N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow 117977. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1479-1488, November, 1995.     

Asymmetric nitrogen−35 : Structure and properties of l(s)-α-carboxyethyl-3, 3-bis(trifluoromethyl)diaziridine and its derivatives

A second-kind asymmetric transformation involving N-atom inversion has been observed at 20° for 1(S) - α - carboxyethyl - 3,3 - bis(trifluoromethyl)diaziridine 1 and its methyl ester 2. X-Ray data for the diastereomer (1S, 2S, α-S), 1A (which is thermodynamically preferred in the crystalline phase), ¹H NMR spectra of ethyl ester 3-¹⁵N(1) and 3-¹⁵N(2), CD spectra of 1A,B, 2A,B, potassium salt 4A,B and semiempirical calculations (MINDO/3 and INDO) for 1A, show that the stereospecificity of crystallization of the diastereomer A is due to the higher energy of the crystal lattice of the diastereomer (1R, 2R, α-S), 1B because of hindered charge compensation as well as to the hindrance by the CF₃, groups to intermolecular H-bonds. According to semiempirical calculations, the stability of 3,3 - bis(trifluoromethyl) - diaziridines (TFD) to the action ofel w-orbital energies and depolarization of the C-N bonds due to hyperconjugation and the inductive effect of the CF₃,-groups. The steric effect of these groups is the reason of the low configurational stability of TFD compared with the 3,3-dimethyl analogues.     

1-(1-Adamantyl)diaziridine

The reaction of 1-aminoadamantane with CH₂O and H₂NOSO₃H in the presence of K₂CO₃ under phase-transfer conditions leads to hitherto unknown 1-(1-adamantyl)diaziridine and (1-adamantyl)aminoacetonitrile, characterized by spectral data. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 861–862, April, 1997.     

Autoassembly of cage structures

The molecular structure of 1,4-dimethyl-2,5-dioxabicyclo[2.2.2]octane-3,6-dione (1) has been determined by X-ray diffraction analysis. The skeleton of dilactone1 has a synchro(+,+,+)-twist conformation with dihedral angles =4.0° for the hydrocarbon bridge bonds and =4.4, 4.6° for the lactone bridge bonds.For the previous paper in the series see Ref. 1.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1965–1968, November, 1994.This work was supported by the International Science Foundation (MCO 000), the Russian Foundation for Basic Research (project code 94-03-08730), and NATO (LG 921193).