摘要:

A direct chemical proof is provided for the occurrence of the sucrose linkage in raffinose and stachyose by isolation of sucrose, after selective removal ofD-galactose units. The procedure used takes advantage of the fact that theD-galactopyranosyl residues contain acis-α-glycol group which, in contrast to thetransglycol group of the other sugar residues, is rapidly attacked by ethanolic periodate. The resulting dialdehyde is alkali-labile and preferentially hydrolyzed with dilute base, the alkali-stable sucrose unit being released intact.

ISSN:0008-4042    

DOI:10.1139/v57-146

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Dibenz[b,f]oxepin and its 10-methyl derivative have been prepared by ring expansion of suitable xanthene derivatives. 2-Flurophenanthrene was synthesized from 2-fluorofluorene.

ISSN:0008-4042    

DOI:10.1139/v57-147

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

It has been found that, while hydroxymercuration of 2-methylcyclohexene leads to a single product, 3-methylcyclohexene gives a nonworkable mixture and 4-methylcyclohexene gives both positional and diastereoisomers of which three of the four have been isolated. The ratio of positional isomers is found to be 5:1 in favor of farthest distance of the methyl group from the mercury atom. The conversion of the chloromercuri-hydroxy-methylcyclohexanes to chloromercuri-methoxy-methylcyclohexanes by potassiumtert-butoxide and dimethyl sulphate has been accomplished. Thus the products of hydroxymercuration have been related configurationally to two of the three products of 4-methylcyclohexene methoxymercuration. Among these products that one is most prevalent in which the mercury is most distant, positionally and confjgurationally, from the methyl group in the alkene.

ISSN:0008-4042    

DOI:10.1139/v57-148

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The reaction between benzyl chloride and potassium amide in liquid ammonia has been shown to yield, in addition to stilbene as the main product, considerable quantities of 1,2,3,4-tetraphenylcyclobutane. The isomer of this compound formed in this reaction is believed to be one that has not been reported previously.

ISSN:0008-4042    

DOI:10.1139/v57-149

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

It is shown that hydrolysis of rhyncophylline with dilute hydrochloric acid gives rhyncophyllal (C19H24O2N2), which contains an aldehyde group but no longer contains the methoxyl, the isolated double bond, and the carbomethoxy group originally present in the alkaloid. Rhyncophyllal is reduced by sodium borohydride to the corresponding alcohol, rhyncophyllal, and this is further reduced by lithium aluminum hydride to dihydrodesoxy-rhyncophyllal (C19H28ON2), which shows the properties of an aromatic amine. Reduction of rhyncophyllal by the Wolff-Kishner reaction gives rhyncophyllane (C19H26ON2), which, when dehydrogenated over palladium–charcoal, yields 3,4-diethylpyridine. Direct dehydrogenation of rhyncophyllal produces β-collidine. On the basis of these as well as previously described results a total structure for rhyncophylline is derived.

ISSN:0008-4042    

DOI:10.1139/v57-150

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Amidomycin, an antibiotic active primarily against yeast, has been isolated from aStreptomycesspecies. The Compound C10H68O12N4. is neutral, optically active, and shows no unsaturation nor characteristic light absorption maxima. It is composed of 4 moles each ofD(−)-valine andD(−)-α-hydroxyisovaleric acid, linked alternately by ester and amide bonds to form a 24-membered ring (I). This structure is assigned from the following observations: on mild alkaline hydrolysis 4 moles of alkali are consumed with formation of a hydroxy acid, C10H19O4N (II). The latter on distillation gave a crystalline lactone, C10H17O3N, considered to be 3,6-diisopropyl-2,5-diketomorpholine (III), which was hydrolyzed to give 1 mole each ofD(−)-valine andD(−)-α-hydroxyisovaleric acid.Amidomycin is closely related to valinomycin, an antibiotic isolated fromStreptomycesfulvissimusand shown to be a 24-membered ring compound containingD(−)-valine,D(−)-α-hydroxyisovaleric acid,L(+)-valine, andL(−)-lactic acid. It also resembles the enniatins, produced by certain species ofFusarium, but differs from these compounds in the number of units in the ring structure as well as in containingD(−)-valine rather than an N-methyl-L-amino acid.

ISSN:0008-4042    

DOI:10.1139/v57-151

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Vapor absorption spectra have been measured for naphthalene, anthracene, and pyrene using a modified Beckman DU Spectrometer. Vapor concentrations were determined using published vapor pressure data, and oscillator strengths were computed for a total of five transitions in the three molecules. It was found that the vapor oscillator strengths are considerably lower than in solution by a factor greater than that predicted by classical theory. An absorption region at about 41,000 cm.−1in anthracene is tentatively assigned as the1B2u+state calculated by Pariser to lie at 42,400 cm.−1.

ISSN:0008-4042    

DOI:10.1139/v57-152

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The photochemical decomposition of ketene at 2700 Å has been investigated at −78 °C. The quantum yield of carbon monoxide is two, indicating that the recombination of methylene radicals does not occur at this low temperature.

ISSN:0008-4042    

DOI:10.1139/v57-153

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A reversible silver − silver chloride reference electrode for use in melts at high temperatures has been developed. It was found that the solution of silver chloride in an equimolar mixture of KCl–NaCl melt is ideal for the range of concentrations studied, i.e. 1.0 × 10−3to 6.0 × 10−2 mole fraction of AgCl.The electromotive force of the voltaic cellin which the half-cell to the right contains the above-mentioned reference electrode, was measured as a function of CoCl2concentration. The applicability of the Nernst equation to this system was established. Deviation from ideality was observed in the case of the solution of CoCl2in the melt solvent, and this was attributed to the formation of a complex. The dissociation constant of this complex was calculated as 4.50 × 10−2at 710 °C.The effect of temperature on the electromotive force of this cell was also measured, and the heat of the cell reaction in the presence of solvent (Co + 2AgCl → CoCl2 + 2Ag) was calculated from the data as 22.8 ± 1.3 kcal.The thermodynamic significance of the standard electrode potential of the Co–Ag voltaic cell, derived experimentally as 0.324 volt, is discussed briefly.

ISSN:0008-4042    

DOI:10.1139/v57-154

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The surface free energy for the interface between crystalline sodium chloride and a saturated alcoholic solution was determined from the solubility of sodium chloride in absolute ethyl alcohol as a function of the particle size of the salt. At 298°K. a value of 171 ergs/cm.2was found. A general discussion of the validity of the Ostwald equation, which relates solubility and particle size, is presented.

ISSN:0008-4042    

DOI:10.1139/v57-155

出版商:NRC Research Press    

年代:1957

数据来源: NRC