摘要:

The first synthesis of the glucosinalbin and glucoaubrietin anions has been achieved by sulfonation and deacetylation of the thiohydroximates obtained by addition of tetraacetyl-glucopyranosyl mercaptan top-acetoxyphenylacetonitrile oxide andp-methoxyphenyl-acetonitrile oxide.

ISSN:0008-4042    

DOI:10.1139/v65-001

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Supersonic molecular beams may be isolated from gas which has been allowed to expand through a nozzle. This paper concerns the kinetic theory of the isolation of such beams, taking into account the effect of collisions in the region between the skimmer and the collimator. These collisions turn out to be important. In particular, they offer an explanation of two interesting phenomena: (a) the existence of amaximumbeam intensity as the distance is varied between the nozzle and the collimating system and (b), in a mixed beam, large increases in the intensity of the heavy gas as its initial concentration is reduced by replacement with a much lighter gas. The theory is compared with various experimental results. Although severe approximations have been introduced into the theory, it appears to predict the above phenomena in a way that is better than qualitative.

ISSN:0008-4042    

DOI:10.1139/v65-002

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v65-003

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The oxymercuration of 4-methylenecyclohexanemethanol intert-butyl alcohol yields 1-chloromercurimethylnorcineole which may be converted to 1-methylnorcineole by borohydride reduction or to 4-chloromercurimethyl-4-↑-hydroxycyclohexane-↓-carboxylic acid. This may be deoxymercurated to 4-methylenecyclohexanecarboxylic acid and reduced with borohydride to 4-↓-methyl-4-↑-hydroxycyclohexane-↓-carboxylic acid.

ISSN:0008-4042    

DOI:10.1139/v65-004

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

A group of polysaccharides, called galactomannans I, were precipitated as their insoluble copper complexes from aqueous solutions of the crude polysaccharides obtained from each of the organisms designated in the title. The five galactomannans I were homogeneous under conditions of electrophoresis and ultracentrifugation and had high positive specific rotations. The major constituent monosaccharide wasD-mannose; amounts ofD-galactose ranged from nil for the polysaccharide fromT. rubrumto 13% for that fromT.schönleinii. Methylation and hydrolysis of the five galactomannans I yielded varying amounts of the following: 2,3,5,6-tetra-O-methyl-D-galactose (not present in the products fromT.rubrum), 2,3,4,6-tetra-O-methyl-D-mannose, 2,3,4-tri-O-methyl-D-mannose, 2,4,6-tri-O-methyl-D-mannose, 3,4-di-O-methyl-D-mannose, and 3,5-di-O-methyl-D-mannose. Periodate oxidation results agreed with the methylation studies. The gross structural features of each galactomannan I appear to be the same, namely, a basic chain of 1 → 6 linked α-D-mannopyranose units for approximately every 22 of which there is a 1 → 3 linked α-D-mannopyranose residue. Branch points occur along the 1 → 6 linked chain at the C2positions of theD-mannopyranose units and once in every 45 units at the C2position of a 1 → 6 linkedD-mannofuranose residue. TheD-galactose in the polysaccharides is present exclusively as non-reducing terminal furanose units; non-reducing terminal units ofD-mannopyranose are also present. The variations in the identities and relative amounts of the non-reducing terminal units were the only apparent differences in the gross structural features within this group of polysaccharides.

ISSN:0008-4042    

DOI:10.1139/v65-005

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Secondary deuterium isotope effects have been measured for the reactions between methyl and methyl-d3iodides and a series of tertiary amines in benzene solvent. Deuterium substitution increased the rate of each reaction but the rate ratios(kH/kD)show no systematic change with variation in the structure of the amine. The isotope effect for the reaction with 2-picoline was measured at different temperatures over a range of 40 deg and shows no change. These isotope effects may be rationalized as internal rotational effects of the methyl group or as solvation effects.

ISSN:0008-4042    

DOI:10.1139/v65-006

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The nuclear magnetic resonances of51V,93Nb,121Sb,123Sb, and181Ta in solutions of the pentafluorides of these elements were measured. All of these nuclei have large electric quadrupole moments. In most cases the chemical species observed was identified by spin-multiplet splitting of the metal resonance. In aqueous 48% HF solutions the181Ta resonance could not be observed; the121Sb and123Sb resonances consist of a symmetrical septet, corresponding to the hexafluoride ion; the93Nb resonance consists of a single exchange narrowed line; and the5IV resonance consists of a symmetrical quintet, corresponding to the VOF4−ion. In alcohol solution NbF5disproportionates to form NbF6−, whereas in ether and triethylamine solutions, the complexes NbF5•OEt2and NbF6•NEt3are formed. The latter complexes were confirmed by proton resonance measurements. Resonances of5IV in aqueous solutions of V2O5and of NH4VO3as a function of pH show a parallel behavior and reveal the presence of six different oxyions of vanadium. Five of these resonances are assigned to the species, VO43−, VO3−, V2O74−V3O106−and VO2+, on the basis of the resonance line width and the pH range in which the resonance appears.

ISSN:0008-4042    

DOI:10.1139/v65-007

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The rates of solvolysis of a series of sulfonium salts which may be considered as models for the biologically important sulfonium salt, S-adenosylmethionine, are discussed in terms of a possible anchimeric role of the carboxyl group of methionine in transmethylation reactions.

ISSN:0008-4042    

DOI:10.1139/v65-008

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

A survey has been made of the reactions of both geometric isomers of phenyl-2-pyridyl ketoxime with metal ions. The complexes of copper(II) with thesyn-phenyl isomer have been investigated. Acid dissociation constants of both geometric isomers, and of the 2:1 copper chelate of thesyn-phenyl oxime have been determined.

ISSN:0008-4042    

DOI:10.1139/v65-009

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The analysis of cyclopropyllithium allows estimates to be made of all proton coupling constants. The exceptionally small couplings across carbon atoms 2 and 3 are examined in the context of correlations of coupling constants with the electronegativities of substituents. It is concluded that, although the couplings involving protons attached to the same carbon as the substituent decrease with increasing electronegativity of the substituent, the opposite is true for couplings involving the protons attached to carbons one bond removed from the substituent. Individual values are suggested for the coupling constants in cyclopropane itself and these agree with the observedI3C side bands in its proton spectrum.

ISSN:0008-4042    

DOI:10.1139/v65-010

出版商:NRC Research Press    

年代:1965

数据来源: NRC