Volume 32, Issue 3

Preparative electrochemical oxidation of branched alkanes in trifluoroacetic acid yields — as function of the applied potential — mono- or bifunctionalized derivatives. Esters with rearranged skeleton (hydride or methyl shift) suggest carbenium ion intermediates. These are generated by oxidative elimination of a proton or fragmentation. A method is described to measure small differences in reactivity of alkanes.

Nitrogen 1 s energies are measured by ESCA for a series of formyl and acetyl derivatives of ammonia and of some alkylated and mercurated ammonium salts. For convenient use in chemical structure analysis the binding energy shifts are correlated with a charge parameter obtained from electronegativity considerations. The shifts are also analyzed in terms of group electronegativities. Comparison between the two classes of compounds gives evidence for π-bonding in formyl and acetyl derivatives of ammonia.

2,2,4,4,6-Pentakisdimethylamino-2,4-diphospha-1,3,5-s-triazine (2), 2,2,4,4-tetrachloro-6-diethylamino-2,4-diphospha-1,3,5-s-triazine (4), and 2,2,4,4,6-pentakisethyleneimino-2,4-diphospha-1,3,5-s-triazine (5) were synthesized by reacting 2,2,4,4,6-pentachloro-2,4-diphospha-1,3,5-s-triazine (1) with the corresponding amines. The products are characterized by their NMR spectra. Attempts to react 1 with alkylation and arylation reagents are described.

15 N chemical shifts, the isotopic effect on chemical shifts and 1 J( 15 N- 15 N) coupling constants of Na 2 N 2 O 3 , K 2 SO 3 N 2 O 2 , Na 2 [CH 2 (N 2 O 2 ) 2 ], [(C 2 H 5 ) 2 NH 2 ][(C 2 H 5 ) 2 NN 2 O 2 ] and N 2 O 3 were measured. The discussion is based on a compilation of reported 15 N- 15 N coupling constants.

Reaction of 2,4,6-trimethyl-1,1,3,3,5,5-hexaoxo-1 λ 6 -,3 λ 6 -,5 λ 6 -,2,4,6-perhydrotrithiatriazin, (CH 3 NSO 2 ) 3 (2), with trimethylamin forms a tetramethylammonium salt N(CH 3 ) 4 ⁺[(CH 3 NSO 2 ) 2 (NSO 2 )]- (3). From 3 a silver-salt can be obtained which reacts with ethyl-iodide to form a mixed alkylated covalent derivative of 2.

The compound Cs[B 5 O 6 (OH) 4 ] · 2 DMSO was prepared by hydrolysis of tris(methoxy)-borane in organic solvents with small amounts of water in presence of cesium tert-butylate and recrystallized in DMSO (dimethyl sulfoxide). Cs[B 5 O 6 (OH) 4 ] · 2 DMSO crystallizes in the monoclinic space group Ρ2 1 /a with a= 9.593(2), b=19.179(4), c= 11.585(2) A, β= 119.99(2)° and Ζ = 4. The crystal structure was determined by single-crystal diffractometer data and refined to a conventional R value of 9.9%. The crystal structure consists of chains of pentaborate anions [B 5 O 6 (OH) 4 ]- linked by hydrogen bonds. The cesium cation and the DMSO molecules join the chains to sheets by coordination and hydrogen bonds respectively.

Crystals of [(C 2 H 5 ) 4 N] 2 [Fe(CN) 4 NO] are rhombic with α = 3392.0(21) [pm], b = 760.4(8) [pm], and c = 983.2(9) [pm]; the space group is Pna2 1 . The structure was determined by three-dimensional Patterson and Fourier methods on the basis of 1363 independent reflections. The unit cell consists of 4 molecular units. The anion forms a tetragonal pyramid which is only slightly distorted by narrowing one of the NC–Fe–NO angles. As expected from the electronic structure the apical NO group is almost linearly bonded to the central atom. The cations occur in two different conformations.

The (2+2) cycloadditions of maleic acid anhydride (MSA) and 1,3-cyclohexadiene (CHD) to ethylene and acetylene were initiated with gamma-rays in different solvents. The four-membered ring products were formed with high selectivity and surprisingly high energy yields in solvents with triplett energies smaller than ethylene and acetylene but higher than MSA and CHD resp. In benzonitrile as a solvent MSA reacts with ethylene to give cyclobutane-1,2-dicarboxylic acid anhydride (1) (G = 0.04) and with acetylene to give cyclobut-3-ene-1,2-dicarboxylic acid anhydride (2) (G = 3.7). The cyclobutene derivative (2) is formed in ≥ 80% yield and the bicyclopropyl derivative (8), which is the main product in the photochemical reaction, with a yield of ≤ 20%. 1,3-Cyclohexadiene was also added to ethylene to give bicyclo(4,2,0)oct-2-ene (G = 0.4) and bicyclo(2,2,2)oct-2-ene (G = 0.1) under gamma irradiation in methylnaphthalene as a solvent. Under similar conditions addition to acetylene gave bicyclo(4,2,0)octa-2,7-diene (G = 0.04) and bicyclo(2,2,2)octa-2,5-diene (G = 0.3), respectively.

The photochemical cyclisation of diphenylether to dibenzofuran is scavenged by trans-1,3-pentadiene indicating that the triplet state of the ether is the reactive species. The intramolecular, kinetic isotope effects k ʜ /k ᴅ for the cyclisation of 2-deuteriodiphenyl ether and 1-phenoxy-4-pentadeuteriophenoxy-benzene are 1.12 ± 0.05 and 1.19 ± 0.05, respectively. A reaction scheme consisting of a photochemical cyclisation to 1 a, 9 a-dihydrodi-benzofuran followed by dehydrogenation to dibenzofuran is suggested.

The reactivity of 2-cinnamoyl-5,6,7,8-tetrahydronaphthalene (1) towards MICHAEL condensation with acetylacetone, ethyl acetoacetate, cyclohexanone and malononitrile were studied. Also, the reaction of hydrazine hydrate, phenylhydrazine, hydroxylamine, with 2 were accomplished. Moreover, cyclization of 9 and 11 were performed.

Using 13 C-labelled compounds it is demonstrated that the extent of carbon randomization preceding or accompanying the ethylene elimination from C 11 H 15+ is strongly influenced by the life time of the ions. Furtheron it is shown that the amount of these isomerisation reactions depends upon the structure of the precursor ions.

Title compounds were prepared through epimerisation of 2-acetamido-2-deoxy-D-glucose in NaOD. The isotopic purity of the products was determined by NMR and mass spectroscopy. The mechanism of epimerisation is briefly discussed.

The (Z,Z)-configuration of the bilivioline chromophoric system was established investigating an appropriate model compound by means of pK measurement, 1 H NMR spectroscopy Lanthanide ion induced shift technique, electron absorption spectroscopy and PPP calculations. Moreover a syn-syn conformation which is twisted at the a-methine single bond and planar within the pyrromethene unit (based on the concept of partial structures of bile pigments) of the molecule was deduced.

o-Phenylenediamine reacts with arylidenecyanoacetic acid derivatives and with analogous arylmethylidenemalononitriles to give 2-arylbenzimidazoles (6). 2-Cyanomethylbenzimidazole (7) reacts with aromatic aldehydes to give 1-aryl-2-cyano-2(2-benzimidazole)ethylenes (8). The reduction products of the latter compounds are, also, presented. Structures of the newly prepared compounds have been proved using micro and spectral analyses.

The behaviour of 3,5-diamino-4-phenylazopyrazole (1) toward isothiocyanates, acrylonitrile and ethyl ethoxymethylenecyanoacetate is investigated. An improved synthesis of 4-unsubstituted-3,5-diaminopyrazoles by an arylazo removal reaction is also reported.

3-Amino-5-phenyl-4-phenylazoisoxazole (1) reacts with ethyl acetoacetate to yield the corresponding ethyl isoxazolylaminocrotonate derivative (2) which could be thermally cyclized into the isoxazolopyrimidine derivative (4). On the other hand, condensation of 1 with ethoxymethylenemalononitrile has resulted in the formation of the aminoethylene derivative (5). Compound 1 reacted with acrylonitrile to yield the isoxazolo[2,3-a]pyrimidine derivative (6). The latter was converted into the corresponding exo derivative (8) by the action of acetic acid-hydrochloric acid mixture. Compound 1 also reacted with methoxycarbonyl-, ethoxycarbomyl- and benzoyl isothiocyanates to yield the isoxazolylthioureas (10a, b) and (11), respectively. The reaction of 2 with acetic acid-hydrochloric acid and with phenylhydrazine is reported.

The yields of 2-deoxy-D-gluconic, D-gluconic and other sugar acids from 60 Co-gamma irradiated (dose rate = 4 Krads/min) D-glucose solutions are reported. The acids produced upon radiolyses were separated from glucose and neutral products by anion exchange, assayed by gas chromatography of the trimethylsilyl derivatives, and definitive identification made by mass spectrometry. In He degassed, irradiated 0.055 M glucose G(2-deoxy-D-gluconic acid) = 0.62 and G(D-gluconic acid) = 0.20. The approximate G values for the other identified acids are: glyceric acid 0.03, 2-deoxy-tetronic acid 0.04, tetronic acid 0.03, 4-deoxypentonic acid 0.02, deoxyketogluconic acid 0.17. In N 2 O saturated glucose solutions D-gluconic acid yields increased by a factor of ∼1.9 while that of 2-deoxy-D-gluconic acid increased by a factor of only ∼ 1.1.

The spin-labeled (1-oxyl-2,2,6,6-tetramethyl-4-piperidyl)-phenyl imidazole-1-phosphonate (4) was used to prepare (1-oxyl-2,2,6,6-tetramethyl-4-piperidyl)phenyl N-alkyl and N-aryl phosphoroamidates (8) in yields generally exceeding 70%. [xxx] Amidates 8 were also prepared from the corresponding chloridate 10. However, in the latter case, a basic condensing agent, such as, triethylamine was essential. The chloridate 10 was converted to the spin-labeled pyrophosphate 11 and the acid 12. [xxx] The pyrophosphate 11 can be employed to phosphorylatively spin-label amines.

The preparation of triacetoneamine (1) by the condensation of acetone with ammonia in the presence of calcium chloride at room temperature is investigated. In addition to 1, acetonin (8), diacetone alcohol (4), mesityl oxide, and diacetoneamine (7) are formed during the reaction. The progress of the reaction is monitored by gas chromatography. The effects of the extent and the rate of stirring, the amount of ammonia introduced on the critical first day of the reaction, and the mesh size and the amount of calcium chloride on the purity and weight yield of 1 are studied. The yield of 1 is maximized by recovery of the unreacted acetone. The reaction at room temperature under optimized conditions is described.

The preparation of triacetoneamine (1) by the condensation of acetone with ammonia in the presence of calcium chloride is investigated. The progress of the reaction is monitored by gas chromatography. The effects of added ammonium chloride, the total amount of ammonia introduced, and the temperature of the reaction on the weight yield and purity of 1 are investigated. The optimized conditions for the preparation of 1 at 59 °C are described.

The title compound is formed in low concentration by addition of selenium to PBr 3 or by reaction of (CH 3 Se)PBr 2 with bromine.

The infrared spectrum of ScVO 4 is reported and discussed in comparison with those of YVO 4 and of the lighter lanthanide orthovanadates. In order to facilitate the vibrational assignment the spectra of a series of solid solutions of the type Sc(VO 4 ) 1-n (PO 4 ) n are also measured and analyzed.

By investigations in the system Ca—Ni—P we found two ternary phases. CaNi 1.95 P 2 crystallizes in a tetragonal lattice; a ThCr 2 Si 2 type structure is supposed. Ca 2.1 Ni 11.9 P 7 crystallizes in a hexagonal lattice.

Four new ternary calcium compounds of zinc (cadmium) with a 5B-element have been prepared. Analytic, pycnometric and X-ray powder data are given. The compounds are supposed to crystallize trigonally in a CaAl 2 Si 2 -type structure.

o-Aminophenols react with organo tin compounds forming stable mesomeric complexes. The structure of one compound was determined by X-ray crystallography. The tin atom is chelated by two oxygen and one nitrogen atom. The nitrogen atom and the associated C and Sn atoms are in a plane and therefore the ESR tin coupling constant has an additional contribution by a π-σ-interaction through the N—Sn bond.

The new intermetallic compound Li 2 Sb has been prepared and its crystal structure has been determined. It crystallizes hexagonally, a = 794.6 ± 0.5 pm, c = 652.7 ± 1.0 pm, c/a = 0.821, space group P 6̅2c–D 3h 4 isotypic with Mg 2 Ga. Relations to the Zintl-phases are discussed.