摘要:

Three new metabolites have been isolated from cultures ofStreptomyces caeruleusand are related to caerulomycin, a known antibiotic metabolite of this organism now designated caerulomycinA. The structures of two of the new compounds, caerulomycinsBandC, are shown to be 3-hydroxy-4-methoxy- and 3,4-dimethoxy-2,2′-dipyridyl-6-(E)-aldoxime.

ISSN:0008-4042    

DOI:10.1139/v77-589

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Details of the synthesis of the tridentate tris chelating ligand dimethyl(N,N-dimethylethanolamino)(1-pyrazolyl)gallate and the preparation and physical properties of the binuclear transition metal complexes incorporating this ligand are given. Crystals of bis-μ-pyrazolyl(N(1),N(2))-bis[dimethyl(N,N-dimethylethanolamino)(1-pyrazolyl)gallato(N(2),O,N)copper(II)] are monoclinic,a = 12.018(2),b = 10.390(1),c = 13.568(3) Å, β = 100.04(6)°,Z = 2, space groupP21/c. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a finalRof 0.045 andRwof 0.058 for 2460 reflections withI ≥ 3σ(I). The centrosymmetric binuclear molecule features copper atoms having distorted square pyramidal co-ordination geometry. Three of the basal positions are occupied by the oxygen, pyrazolyl nitrogen, and amino nitrogen atoms of the tridentate tris-chelating ligand. The two remaining sites are occupied by bridging pyrazolyl groups, which provide a basal nitrogen atom to one copper atom and an apical nitrogen atom to the second copper centre. The gallium atoms have distorted tetrahedral coordination geometry. Important bond lengths (corrected for libration) are: Cu—O, 1.981(3), Cu—N(basal), 1.953(3)–2.143(4), Cu—N(apical), 2.173(3), Ga—O, 1.907(3), Ga—N, 1.991(4), and Ga—C, 1.962(7) and 1.977(7) Å.

ISSN:0008-4042    

DOI:10.1139/v77-590

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Crystals ofL-prolinatodimethylgallium are orthorhombic,a = 10.624(2),b = 10.567(4),c = 8.2268(6) Å,Z = 4, space groupP212121. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a finalRof 0.029 andRwof 0.035 for 1109 reflections withI ≥ 3σ(I). Details of the preparation and physical properties ofL-prolinatodimethylgallium andL-prolinatodiethylgallium are given. The crystal structure ofL-prolinatodimethylgallium consists of molecules each linked to two others by weak Ga—O bonds (2.695(3) Å) and N—H … O hydrogen bonds (N … O = 2.901(4) Å) to form a chain-like polymeric structure extending along thebaxis. The gallium atom is five-coordinate and has distorted trigonal bipyramidal geometry. Important bond lengths are: Ga—O (axial), 2.044(3) and 2.695(3); Ga—N, 2.035(3); and Ga—C, 1.942(5) and 1.958(5) Å

ISSN:0008-4042    

DOI:10.1139/v77-591

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A method is reported for the resolution of (±)-trans-2-benzylaminocyclopentanol usingD-orL-dibenzoyltartaric acid as the resolving agent. Debenzylation of the enantiomeric bases gives the enantiomerictrans-2-aminocyclopentanols. These compounds have been converted to their quaternary ammonium acetate ester derivatives and the absolute configuration assigned by comparison of the ord spectra with the spectra of the appropriate cyclohexane derivatives.

ISSN:0008-4042    

DOI:10.1139/v77-592

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

As a test for possible competitive α- and β-enolization in bicyclic ketones the behavior of bicyclo[2.2.2]octenone int-BuO−–t-BuOH at 185 °C has been examined. The major reaction (∼90%) involves Claisen condensation followed by retro Diels-Alder elimination of ethylene and Haller–Bauer cleavage. All acidic and phenolic components, accounting for 90% of the product, have been identified and characterized, primarily by their13Cmr spectra.

ISSN:0008-4042    

DOI:10.1139/v77-593

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Dihydro-TCNDQ was prepared from biphenyl. The dianion salts of TCNDQ with alkali metal and tetraalkylammonium counter ions were prepared and characterized by their nmr and uv-visible spectra. Solutions of these dianions undergo two one-electron oxidations at −0.31 and −0.15 V in DMF. The electrochemistry is complicated by a second chemical process involving the monoanion. This was postulated to involve a dimerization ofand this process was also implicated in the analysis of the uv-visible spectra of this anion. Theanion has a solution esr spectrum of over 25 lines which have been analyzed by a computer simulation of the spectrum.

ISSN:0008-4042    

DOI:10.1139/v77-594

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

In the presence of an allylic bromide, aldehydes, but not ketones, react with cyanide ion under phase-transfer catalysis to give cyanohydrin allyl ethers which can be converted to ketones. Other alkylating agents and nucleophiles give different results. Replacing the allylic bromide with acetic anhydride leads to cyanohydrin acetates.

ISSN:0008-4042    

DOI:10.1139/v77-595

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Crystals of hexamethylcyclotriphosphazene are monoclinic,a = 12.084(2),b = 13.426(1),c = 15.488(2) Å,β = 102.92(2)°,Z = 8, space groupC2/c. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a finalRof 0.045 andRwof 0.060 for 1922 reflections withI ≥ 3σ(I). The six-membered phosphazene ring is slightly nonplanar and has a distorted chair conformation. Important molecular dimensions (bond lengths are corrected for libration) are: P—N, 1.599(2)–1.612(2), P—C, 1.796(3)–1.823(4) Å, N—P—N, 115.7(1)–117.9(1), P—N—P, 122.1(1)–122.9(1), and C—P—C, 101.8(2)-103.1(2)°.

ISSN:0008-4042    

DOI:10.1139/v77-596

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The method developed by Osterberg, Sarkar, and Kruck for obtaining the concentrations of free ions in solutions of complex equilibria from pHtitration data has been studied to establish the conditions under which the method gives accurate values for free ligand and free metal concentrations in systems containing a variety of complexes, including protonated, hydroxy, mixed ligand, and polynuclear complexes. Simulated titration data have been used so that the true values of free ligand and free metal concentrations would be known. Calculation procedures are described for each step in the data evaluation, including procedures for extracting information about the stoichiometry of the complexes from the unique information provided by this method. The effect of various systematic and random errors is also considered.

ISSN:0008-4042    

DOI:10.1139/v77-597

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The heat of formation of bromopentafluorobenzene has been determined through the use of the direct combustion method which has been applied to hexafluorobenzene, octafluorotoluene, and iodopentafluorobenzene. While a platinum lined bomb is normally used for these types of compounds a steel bomb had to be adopted in this work. The combustion of bromopentafluorobenzene in the steel bomb yields CO2, CF4, F2, Br2, and BrF3. With a ten-fold excess of oxygen, the average CO2to CF4molar ratio is 7.29 ± 0.07. A material balance was obtained for carbon, fluorine, and bromine. The value of ΔHf2980(C6F5Br, g) = −711.6 ± 16.7 kJ mol−1(−170.1 ± 4.0 kcal mol−1) has been combined with ΔHf2980(C6F5, g) = −387.4 kJ mol−1(−92.6 kcal mol−1) and ΔHf2980(Br, g) = 111.7 kJ mol−1(26.7 kcal mol−1) to obtain a value forD[C6F5—Br] of 435.9 kJ mol−1(104.2 kcal mol−1).

ISSN:0008-4042    

DOI:10.1139/v77-598

出版商:NRC Research Press    

年代:1977

数据来源: NRC