Degenerate rearrangement of detectable 9,10-dimethyl-9-vinyl-phenanthrenium ion: 1,2-Shift of the vinyl group

Dynamic NMR study showed that 9,10-dimethyl-9-vinylphenanthrenium ion, generated under the conditions ensuring its “long life,” undergoes very fast (ΔG ^≠ = 24.4 kJ/mol at ?103°C) degenerate 1,2-shift of the vinyl group. According to the DFT quantum-chemical calculations, the process is one-step, and the low energy of formation of the activated complex is determined by effective participation of π electrons of the vinyl group in delocalization of the positive charge; no such delocalization is intrinsic to the initial ion.     

Degenerate rearrangement of 9-isopropenyl-9,10-dimethyl-phenanthren-9-yl and 9,10-dimethyl-9-(trans-1-methylprop-1-en-1-yl)phenanthren-9-yl cations

¹H NMR study has shown that long-lived 9-R-9,10-dimethylphenanthren-9-yl cations (R = isopropenyl, trans-1-methylprop-1-en-1-yl) generated in the system HSO₃F-SO₂ClF-CD₂Cl₂ at ?130°C undergo degenerate rearrangement via 1,2-vinyl shifts (ΔG’ = 37 and 39 kJ/mol, respectively, at ?88°C). Analysis of the geometric parameters of the initial structures and transition states calculated by the DFT method indicates that unfavorable steric factors are responsible for the sharp deceleration of 1,2-shifts of the isopropenyl and trans-1-methylprop-1-en-1-yl groups as compared to vinyl and cis-1-methylprop-1-en-1-yl groups, respectively.     

Conversion of 9-hydroxy-10-methyl-9,10-dihydroacridine into bis(10-methyl-9,10-dihydroacridin-9-yl)ether

The action of aqueous alkali on N-methylacridinium salts gives as the main product bis-(10-methyl-9,10-dihydroacridin-9-yl) ether, and not 9-hydroxy-10-methyl-9,10-dihydroacridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1119–1121, August, 1970.     

Crystal structure of 2-Se-(2-methyl-2-propenyl)-1-benzoic acid.

C11H12O2Se is triclinic, P1. Unit-cell dimensions at 293 K are a = 5.8450(10), b = 8.1490(10), c = 11.4620(10)A, alpha = 97.050(10), beta = 90.140(10), gamma = 90.120(10) degrees, V = 541.81(12)A3, Dx = 1.564 g/cm3, and Z = 2. The R value is 0.047 for 1388 observed reflections. The dihedral angle between the phenyl ring and the isobutenyl group is 72.3(2) degrees. There is an intermolecular hydrogen bond between two symmetry-related carbonyl groups with an O1...O2 distance of 2.669(6)A. The molecules in the crystal are packed at normal van der Waals distances.     

Molecular and crystal structure of 2-(2-methyl-2-propenyl)-1,3-cyclopentanedione (C9H12O2)

An x-ray crystal structure study of 2-(2-methyl-2-propenyl)-1,3-cyclopentane-dione (C₉H₁₂O₂) has been carried out. It has been shown that in the solid this compound occurs exclusively in the enol form. The molecules are bound together by strong hydrogen bonds and form infinite chains along the b-axis. According to the spectroscopic data (¹H and¹³C NMR), the same compound in solution has a mesomeric structure.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1794–1797, August, 1991.     

Synthesis of Bioactive Pyrethroid, 3-Phenoxybenzyl 1R-trans-2, 2-Dimethyl-3-(2-chloro-1-propenyl) Cyclopropanecarboxylate

The title compound 1 has been prepared from (+)-3-carene (2) and found to have the same order of activity as its IR-cis isomer 3 reported by us earlier¹ The key intermediate methyl IR-trans-2, 2-dimethyl-3-(2-oxopropyl)cyclopropanecarboxylate (4) has been characterised.     

The chemistry of polycyclic arene imine. VI. 1-[N,N-di-(2-propenyl)-9-phenanthreneamine-10-yl]-1a,9b-dihydrophenanthro[9,10-b]azirine an unusual allylation product of phenanthrene 9,10-imine

Phenanthrene 9,10-imine (1) was shown to react with allyl bromide and 50% aqueous sodium hydroxide under phase transfer catalysis conditions to give the title compound 3 as the only product. The starting imine 1 is assumed to undergo initially bis alkylation to form an N,N-di-(2-propenyl)phenanthrene 9,10-iminium salt (4) which, in turn, is attacked by a deprotonated phenanthrene imine anion (5). The structure of 3 has been determined by a single crystal X-ray diffraction analysis.     

Synthesis and properties of 2-(2-furyl)-1-methyl-1H-acenaphtho[9,10-d]imidazole

2-(2-Furyl)-1-methyl-1H-acenaphtho[9,10-d]imidazole was obtained by the condensation of 9,1-acenaphthenequinone with furfural in the presence of ammonium acetate followed by N-methylation of the obtained 2-(2-furyl)-1H-acenaphtho[9,10-d]imidazole with methyl iodide in N-methylpyrrolid-2-one in the presence of potassium hydroxide. It was established that its electrophilic substitution in an acidic medium only takes place at position 2 of the furan ring while in a neutral medium both position 2 and position 7 of the aromatic part of the molecule undergo electrophilic attack. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 191–196, February, 2006.     

Synthesis and Crystal Structure of cis - 1,2- Dicy ano- 1,2- b is（ 2- me thyl- 4-bromo-3-thienyl）ethane

The title compound cis-1,2-dicyano-1,2-bis（2-methyl-4-bromo-3-thienyl）ethane has been synthesized and structurally characterized by X-ray single-crystal diffraction method. Crystal data： triclinic, space group P1^1, Z = 2, C14H8Br2N2S2, Mr = 428.16, a = 6.9410（5）, b = 11.0150（9）, c = 11.1760（8） A, α = 70.3390（10）,β = 76.1860（10）, γ = 79.5490（10）°, V= 776.59（10） A^3, Dc = 1.831 g/cm^3, μ（MoKα） = 5.478 mm^-1, F（000） = 416, R = 0.0487 and wR = 0.1453 for 2456 observed reflections with I 〉 2σ（/）. X-ray analysis reveals that the two thiophene rings are significantly twisted with an average dihedral angle of 57.45°. The molecule adopts a photo-active antiparaUel conformation and the distance between the two reactive C atoms of thiophene rings is 3.465（8）A. These structural elements which exhibit a suitable geometry are extensively explored for photochromic behavior in the crystalline state.