摘要:

The extraction efficiencies of various solvents for toxic organic compounds on municipal incinerator flyash were examined. Soxhlet extraction by the solvent was followed by benzene Soxhlet extraction for determination of the non-extracted material. Benzene was found to be the best solvent when considering purity and extraction of hazardous compounds.

ISSN:0008-4042    

DOI:10.1139/v84-446

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

A study by dielectric polarization, microcalorimetry, and infrared spectrometry has allowed us to demonstrate the role played by the halogen in interactions between a series of chlorinated and brominated derivatives of methane (considered as types of halogenated anesthetics) and two tertiary amides taken as models for an element of the membranes of the nervous cells. The inert organic solvent used was cyclohexane. The interactions are of the hydrogen bonding and (or) halogen bonding types.

ISSN:0008-4042    

DOI:10.1139/v84-447

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

An investigation of the peroxidation of cyclohexene to formcis1,2-cyclohexanediol has been continued using an improved turbulent stirring apparatus. Varying conditions of temperature, methanol concentration, dilution, and permanganate/cyclohexene ratios have been evaluated by the method of comparative product yields. The temperature effect was quite modest since only at the extremes of −20 and 40 °C were decreases in yields noted. Added methanol in low concentrations, > 10%, gave slightly increased yields, but decreased yields were observed when methanol was added in 75% concentration. Under the new stirring conditions, 83–86% yields were obtained with ~0.05 Madded potassium permanganate, but only 70–74% yields were obtained at higher concentrations. This effect appeared to relate to the increased viscosity of the mixture which results from the formation of gelatinous manganese oxides. Ratios of cyclohexene to permanganate ion greater than 2:1 gave no significant yield increases, based on permanganate utilization. All of the above data have been interpreted with the assumption of an intermediate alkene – permanganate ion addition complex. Preparative scale syntheses ofcis-1,2-cyclohexanediol have produced 83–87% yields with either 0.2 or 0.5 molar quantities of cyclohexene.

ISSN:0008-4042    

DOI:10.1139/v84-448

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Crystals of acyclovir belong to the space groupP21/n, and the cell dimensions area = 25.459(1),b = 11.282 (1),c = 10.768(1) Å, β = 95.16(1)°. Intensity data were measured on a diffractometer and the structure was determined by direct methods. The asymmetric unit was found to contain three independent molecules of acyclovir and two molecules of water. Least-squares refinement, which included all hydrogen atoms, converged atR = 0.053 for 3970 observed reflections. In two of the molecules the side chain is partially folded, while in the third one it is fully extended. The glycosidic torsion angles are in the range 91.4–104.3°. The conformational features are compared with those in other known acyclonucleosides. They are also examined in relation to the behavior of acyclonucleosides and acyclonucleotides in various enzymatic systems, including those related to antiviral activities.

ISSN:0008-4042    

DOI:10.1139/v84-449

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

The reactions of 4-X-phenyl-4-nitrophenylcyanomethanes with tetramethylguanidine in acetonitrile solvent give carbanionic products absorbing in the range λmax580–650 nm. The equilibrium constants are all large, in excess of 6000 dm3mol−1. For a series of deprotonation reactions with X = NO2, Cl, Br, H, and OCH3, the Hammett ρ value is 2.03 ± 0.03. For the same compounds, the primary deuterium isotope effect,kH/kD, varies from 8.9 for X = NO2to 14.0 for X = OCH3at 25 °C.

ISSN:0008-4042    

DOI:10.1139/v84-450

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Three types of complexes,trans-[Pt(LH)2Cl2], [Pt(L)2], and [Pt(LH)2(SR)2] where LH = NH2—C(CH3)2(CH2OH) and NH2—C(CH2OH)3and L are the deprotonated ligands, have been synthesized.The crystal structure oftrans-[Pt(NH2—C(CH3)2CH2OH)2Cl2] has been determined by X-ray diffraction methods. The crystals are monoclinic, space groupP21/c, witha = 6,282(3),b = 20,901(13),c = 10,769(10) Å, β = 92,64(6)°, andZ = 4. The structure was refined by full-matrix least-squares analysis to a conventionalRfactor of 0.049 andRw = 0.042. The coordination around the platinum atom is square planar. The Pt—Cl distances are 2.306(2) and 2.309(3) Å and the Pt—N bonds are 2.060(8) and 2.071 (7) Å. The hydroxyl oxygen atoms are disordered; the disorder is different for each organic ligand. The structure is stabilized by an extensive hydrogen bonding system.

ISSN:0008-4042    

DOI:10.1139/v84-451

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

An analysis of the preferred conformations and modes of self-association of theN-fluoren-9-methoxycarbonyl derivatives ofL-alanine and α-aminoisobutyric acid was performed in solution and in the solid state using infrared absorption,1H nuclear magnetic resonance, and X-ray diffraction. In a solvent of low polarity (deuterochloroform) non-associated and self-associated species (involving predominantly the hydroxyl and carbonyl groups of the carboxylic acid moiety) simultaneously occur. At high dilution, where self-association is absent, the amount of intramolecularly H-bonded forms, if any, should be extremely small.Z(trans)E(cis) isomerism about the amide bond of the secondary urethane moiety was observed only for the less bulkyL-alanine derivative. In the solid state all H-bonding donors and acceptors of theL-alanine and α-aminoisobutyric acid derivatives take part to complex schemes of intermolecular H-bonds. In theL-alanine derivative, crystallized as monohydrate, most of the intermolecular H-bonds involve the water molecule. Intramolecular H-bonds are not observed in either compound. The conformation about the secondary urethane CO—NH bond isZ(trans) in both compounds. BothL-alanine and α-aminoisobutyric acid residues are partially folded. The observation of the long C(sp3)—O bond of the fluoren-9-yl-methoxycarbonyl moiety might contribute to explain the unexpected experimental result that this protecting group can be removed by catalytic hydrogenation.

ISSN:0008-4042    

DOI:10.1139/v84-452

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

The chloroindolenines of deserpidine and reserpine, and the isomeric chloroindolenines derived from yohimbine – characterized for the first time – have been treated with methanol and methoxide ion under a variety of conditions. In the traditional medium of methanolic hydroxide, chlorodeserpidine partially undergoes rearrangement to imino ether, whereas chlororeserpine suffers only substitution of chloride by methoxide; only the α-isomer of the two yohimbine chlorides undergoes rearrangement to a methyl imino ether, the β-isomer being degraded to an intractable mixture. In refluxing neat methanol, the α-chloride of yohimbine rearranges readily and cleanly to imino ether at a rate comparable to that of chlorodeserpidine rearrangement, but vastly greater than that of the β-chloride. However, under silver oxide catalysis all the chloroindolenines rearrange at closely similar rates. The rearrangement of chloroindolenine to methyl imino ether is stereospecific, α-chloride leading to α-spiro imino ether and β-chloride to β-spiro imino ether. The results are rationalized on the basis of stereoelectronic considerations applied to a process of addition of methanol to the imine bond, followed by elimination of hydrogen chloride from the methanol adduct.

ISSN:0008-4042    

DOI:10.1139/v84-453

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

The total synthesis of petasitolone (1), a sesquiterpenoid of the eremophilane family, has been accomplished. The key step of this efficient synthesis is the Lewis acid catalyzed Diels–Alder addition of 2-carbomethoxy-2-cyclohexenone (3) to diene9. The cycloaddition, which gives adduct16in good yield, facilitates the rapid construction of the parent ring system of the target molecule and allows an excellent control of the required stereochemistry.

ISSN:0008-4042    

DOI:10.1139/v84-454

出版商:NRC Research Press    

年代:1984

数据来源: NRC

ISSN:0008-4042    

DOI:10.1139/v84-455

出版商:NRC Research Press    

年代:1984

数据来源: NRC