摘要:

The crystal structures of a number of copper selenides have been re-examined using X-ray powder diffraction intensity data. |F0| values for Cu1•8Se at room temperature (a = 5.765 Å) are satisfied by a model based on space group Fm3m with 4 Se atoms per unit cell on the fcc sites, 5.2 Cu atoms on the tetrahedral sites, and 2.0 Cu atoms on the trigonal sites in the Se sublattice. Cu3Se2is tetragonal,a = 6.402, c = 4.279 Å, with Cu(1) in 2(a), Cu(2) in 4(e) with x = 0.147 ± 5, z = 0.781 ± 9, and Se in 4(e) with x = 0.272 ± 3, z = 0.264 ± 7. CuSe2has the orthorhombic C18 marcasite structure, Pnnm, a = 5.005, b = 6.182, c = 3.740 Å, with Cu in 2(a), and Se in 4(g) with x = 0.184 ± 1, y = 0.385 ± 1. CuSe2II has the cubic C2 pyrite structure, Pa3, a = 6.116 Å, with Cu in 4(a), and Se in 8(c) with x = 0.3891 ± 5.Neither αCuSe nor γCuSe have the CuScovellitestructure.These results are discussed in some detail.

ISSN:0008-4042    

DOI:10.1139/v76-122

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The Diels–Alder adduct of cyclopentadiene and β-bromo acrylic acid1was converted toD,L-exo-6,7-(dihydroxy-di-O-isopropylidene)-2-hydroxy-3-oxabicyclo[3.2.1]octane (9) in an eight-step sequence and a 24% yield based on1. Alternatively, the hemiacetal9was obtained in five steps and 22% yield from norbornadiene through the intermediate lactone11. The thiosemicarbazone and semicarbazone of9were prepared. The synthesis of the free aldehyde13as well as that of the Wittig reaction products12and19are described.

ISSN:0008-4042    

DOI:10.1139/v76-123

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Condensation of lactone1and aminoguanadine provides the amino-triazole carbocyclic analogue ofC-nucleoside2a. Lead tetraacetate oxidation of the semicarbazone derivative4leads to the amino-oxadiazole derivative5. Isoxazolines11and12are obtained by 1,3-dipolar addition of mesitonitrile oxide with the α,β-unsaturated ester13. Addition of diazomethane onto ester13gives the pyrazoline16which can be oxidized with bromine to the corresponding carboethoxy-pyrazole17. The latter is converted to the carboxamido-pyrazole18by treatment with ammonia.

ISSN:0008-4042    

DOI:10.1139/v76-124

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The title compound5was synthesized by adding nitroso derivative2eto cyclopentadiene. The resulting adduct was reduced with diborane followed by acetic acid, and the dinitrobenzoyl group then removed with potassium hydroxide or ammonia.

ISSN:0008-4042    

DOI:10.1139/v76-125

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The following substrates react with sulfurated sodium borohydride, NaBH2S3, to give the corresponding products as shown by the formulas in parentheses: azobenzene, azoxybenzene, phenyl isocyanate (C6H5NH2, C6H5NHCH3),N-nitrosodiphenylamine ((C6H5)2NH, (C6H5)2NNH2), diphenylcarbamyl chloride ((C6H5)2NH), phenyl isothiocyanate (C6H5NH2), benzyl carbamate (C6H5CH2OH), benzylN-phenylcarbamate (C6H5CH2OH, C6H5NH2, C6H5CH2SH), benzyl nitrite (C6H5CH2OH), benzyl nitrate (C6H5CH2OH), benzyl thiocyanate (C6H5CH2S2CH2C6H5), and pyridine-1-oxide (C5H5N). Benzotriazole, pyridine, phthalimide, andN,N′-diphenylurea were found to be stable towards NaBH2S3.The advantage of sulfurated sodium borohydride, NaBH2S3, over sodium borohydride, NaBH4, as a reducing agent was also proven when it was found that most of the above substrates were inert toward NaBH4except for the following organic nitrogen compounds which reacted with NaBH4to give the products indicated in parentheses:N-nitrosodiphenylamine ((C6H5)2NH), diphenylcarbamyl chloride ((C6H5)2NCH3), phenyl isothiocyanate (C6H5NHCH3), benzylN-phenylcarbamate (C6H5CH2OH, C6H5NHCH3), and benzyl thiocyanate (C6H5CH2-S2CH2C6H5).

ISSN:0008-4042    

DOI:10.1139/v76-126

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The behaviour of manganese(II) perchlorate in aqueous perchloric acid solutionwas studied by epr at 25 and 55 °C. The broadening of the band following addition of HClO4considerably exceeds that normally caused by the increase in the viscosity. This result is interpreted in terms of the formation of an internal monoperchlorato complex in equilibrium with the external complex. The decrease in the relative intensity of the signal following addition of HClO4confirms the presence of an internal monoperchlorato complex and permits the evaluation of its stability constant, (8.0 ± 1.5) × 10−2. The relative stability of the Mn(II) monoperchlorato complex compared to those of Co(II) and Ni(II) is explained by a consideration of the ligand field stabilization energy. [Journal translation]

ISSN:0008-4042    

DOI:10.1139/v76-127

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A new total synthesis of racemic 3-hydroxyisomorphinans (3), 3-hydroxyhasubanans (9), 3,9α-dihydroxyhasubanans (5), and 3,9β-dihydroxyhasubanans (7), via 4a-(2-aminoethyl)-1,2,3,4,4a,9-hexahydro-6-methoxyphenanthrene (1a) is described.

ISSN:0008-4042    

DOI:10.1139/v76-128

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The infrared spectra of the isotopically isolated NH3D+ion in polycrystalline ammonium perrhenate, NH4ReO4, and ammonium tetrachlorocuprate(II) dihydrate, (NH4)2.CuCl4.2H2O, have been recorded at room and liquid-nitrogen temperatures. In the crystals of both compounds the ammonium ions are located at sites ofS4symmetry. The N—D stretching mode of NH3D+in NH4ReO4is a singlet, as expected for this site symmetry. In (NH4)2.CuCl4.2H2O, however, a doublet is observed which reveals the occurrence of two non-equivalent orientations of the ammonium ion. The spectra of the undeuterated compounds contain bands due to combination modes involving the librations of the ammonium ion. This shows that the ions are non-rotating.

ISSN:0008-4042    

DOI:10.1139/v76-129

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Ionization values for the deprotonation of the methiodide salts1–8, which occurs in strongly basic DMSO/water mixtures containing 0.047 Mbase, are used to determine pKavalues by the Bunnett–Olsen and Marziano–Cimino–Passerini techniques, which involve extrapolation to the purely aqueous state. The resulting values are compared with those obtained using theH0qacidity function; agreement is good in most cases.

ISSN:0008-4042    

DOI:10.1139/v76-130

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The influence of the environment near the radical site on the stereoselectivity of the homolytic substitution reaction of variously substituted cyclohexyl radicals on the peroxidic oxygen of a peroxy acid has been studied using the thermal decarboxylation of peroxy acids. This reaction leads to stereoisomeric alcoholsThe radical behaves as if it were planar and, in general, an axial approach of the reagent is strongly favoured except when substituents increase the steric hindrance of the radical.The stereoselectivity is explained in terms of the relative importance of steric effects (for the axial approach) and of bond interactions (for the equatorial approach). It also depends on the flexibility of the ring. [Journal translation]

ISSN:0008-4042    

DOI:10.1139/v76-131

出版商:NRC Research Press    

年代:1976

数据来源: NRC