摘要:

Passage of C1to C5haloalkanes through SnCl2–KCl melts results in halide exchange reactions, alkene formation, and rearrangement (including cyclization) reactions of the organic molecules. Relative reactivities, product distributions and melt composition effects are consistent with a carbonium ion mechanism in which the melt functions as a halide ion acceptor. Some control of product distribution by choice of Lewis acid character of the melt seems possible.

ISSN:0008-4042    

DOI:10.1139/v71-001

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The exchange reaction betweent-butyl cation and isobutane in sulfur dioxide solution is first order in both species withEa = 3.6 kcal/mole and ΔS*298 = −27 e.u. No reaction is observed, under these conditions, between thet-butyl cation andn-butane or neopentane. In a similar system the isopropyl chloride – arsenic pentafluoride complex reacts rapidly withn-butane to yield propane and thet-butyl cation, but does not react with neopentane or cyclopropane. An exchange reaction was also observed between the isopropyl chloride – arsenic pentafluoride complex and propane.

ISSN:0008-4042    

DOI:10.1139/v71-002

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

An efficient total synthesis of the racemic forms of the novel tricyclic sesquiterpenes α-cubebene (1) and β-cubebene (2) is described. The key step of this synthesis involved the cupric sulfate catalyzed intramolecular cyclization of the olefinic diazoketone3, which produced, in high yield, ( ± )-β-cubebene norketone (24) and ( ± )-1,6-epi-β-cubebene norketone (25), in a ratio of approximately 3:5, respectively.

ISSN:0008-4042    

DOI:10.1139/v71-003

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Well-resolved electron spin resonance (e.s.r.) spectra are reported and analyzed for the radicals produced when samples of solid adamantane doped with alkyl substituted cycloalkenes are γ-irradiated at room temperature.

ISSN:0008-4042    

DOI:10.1139/v71-004

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The mechanism of the photooximation of alkanes with nitrosyl chloride has been reinvestigated. The lack of initiation of the reaction with free radical initiators suggests that a free radical chain pathway is not involved. Nevertheless, the relative reactivities of hydrocarbons of different structure and the deuterium isotope effect are very similar to those obtained in chlorinations with elemental chlorine, and in particular, primary and tertiary hydrogens are not inert to photooximation as has been previously supposed. A probable reaction mechanism involves hydrogen abstraction from the substrate by atomic chlorine in a free radical non-chain process. This hydrogen abstraction step is shown not to be significantly reversible.

ISSN:0008-4042    

DOI:10.1139/v71-005

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The reactions of the nitrogen oxides, N2O, NO, N2O3, NO2(N2O4), and N2O5, the oxychlorides ClNO and ClNO2, and the oxyanions NO2−and NO3−with the fluorosulfonating agents S2O6F2and BrOSO2F are studied systematically in regard to the formation of nitrosonium and nitronium fluorosulfate. Complex reactions are found when N2O3and N2O4are used as substrates, resulting in mixed or impure products. An explanation involving the intermediate oxidation into N2O5is put forward to explain the results.The solid products NOSO3F and NO2SO3F are characterized by powder X-ray analysis, infrared and Raman spectroscopy, and their solution behavior in HSO3F. Whereas NOSO3F has been found to have an orthorhombic lattice, NO2SO3F crystallizes in the monoclinic system. Unit cell parameters are reported. The vibrational spectra are interpreted in terms of ionic compounds NO+SO3F−and NO2+ − SO3F−. The SO3F−anion, however, appears to be perturbed and all theEmodes are slightly split. No unambiguous evidence for a previously reported non-linear NO2+cation is found. Force constants for this species are calculated assumingD∞hsymmetry.Both compounds are found to be completely dissociated in HSO3F as evidenced by conductometry and1H and19F nuclear magnetic resonance (n.m.r.) spectroscopy.

ISSN:0008-4042    

DOI:10.1139/v71-006

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The pyrrole Grignard reagent reacts with ethyl thiocarbonates to give good yields of ethyl 2-pyrrole-thiocarboxylates.Diethyl carbonate, by contrast, in accordance with earlier reports gives almost exclusively ethyl 1-pyrrolecarboxylate.2-Pyrrolecarbonitrile was prepared in good yield from the pyrrole Grignard reagent and ethyl thiocyanate.

ISSN:0008-4042    

DOI:10.1139/v71-007

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The hot water extractives of the fresh smooth green bark and the fresh leaves of aPopulus deltoidesBartr. tree cut in June and processed by the Waring Blendor technique in ethanol were extracted fractionally with ethyl acetate, and the individual ethyl acetate extracts were fractionated by elution chromatography with water, 20% ethanol, and 50% ethanol on polyamide columns. Important components found in the bark were salicortin, salicin, salicyl alcohol, pyrocatechol, ω-salicyloylsalicin, grandidentatin, grandidentoside, populoside, trichocarposide, and 6-methyldihydroquercetin. Important components found in the leaves were salicortin, salicin, salicyl alcohol, pyrocatechol, 1-O-p-coumaroyl-β-D-glucoside, populoside, ω-salicyloylsalicin, chrysin-7-glucoside, and a new glucoside, deltoidin, which has been identified as 2-O-salicyloylsalicin.

ISSN:0008-4042    

DOI:10.1139/v71-008

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The effect of ligand substitution on bonding to other ligands has been investigated in a series of V(III) complexes. Nuclear magnetic resonance (n.m.r.) contact shifts have been utilized for this purpose. These shifts are interpreted as arising from metal to ligand charge transfer. The results obtained are contrary to those expected from simple considerations of the electron withdrawing or donating abilities of the substituents. Electron withdrawing substituents decrease the charge transfer to the substituted ligand and increase the charge transfer to the remaining ligands. Electron donating substituents have the opposite effect. A simple interpretation is proposed to account for these results. An electron withdrawing substituent on a ligand in thexyplane increases the occupancy of dxywhich cannot interact with the π system of the ligand in thexyplane but which is available for π bonding with the remaining ligands. Effects of this type are to be anticipated whenever the filling of thet2gorbitals is not symmetrical.

ISSN:0008-4042    

DOI:10.1139/v71-009

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The diffusion coefficients in air of carbon tetrachloride, chloroform, and methylene chloride have been measured over a temperature range from room temperature to close to their boiling points by a modified rate of evaporation method. It was shown that considerable error can occur in diffusion coefficients determined by the rate of evaporation method when gas imperfections are ignored.

ISSN:0008-4042    

DOI:10.1139/v71-010

出版商:NRC Research Press    

年代:1971

数据来源: NRC