摘要:

The hydrogen phthalate ester oftrans-l,2-dimethylcyclohexanol was prepared by using phthalic anhydride enriched in18O. The ester was partially decomposed at 128°. An observed enrichment of18O in the alcohol portion of the undecomposed ester supports an earlier postulate that an ion pair is involved in the thermal decomposition of this sterically hindered ester.

ISSN:0008-4042    

DOI:10.1139/v67-111

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Diethylphosphine and methanethiol react with the cyclobutenes(X = Cl, F) to give the compounds (C2H5)2(Y = Cl, F) and(Y = F, Cl, C2H5). The disubstituted compoundis also obtained from CH3SH and.The related di(tertiary phosphine) (C6H5)2-can similarly be prepared. Methanethiol adds toto give the cyclobutane, but reacts withto giveand withto give the cyclobutenone. Tetra-methyldiphosphine andyield the disubstituted compound, whereas a cyclobutenone is obtained when (C6H5)2P—P(C6H5)2reacts with. In some reactions, the phosphorane (C6H5)2PF3is obtained, probably from (C6H5)2PF.

ISSN:0008-4042    

DOI:10.1139/v67-112

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The kinetics and products of the pyrolysis of 3-vinyl-1-pyrazoline (1) are described. The pyrolysis of 3-vinyl-1-pyrazoline-5,5-d2(II) produces vinylcyclopropane-2,2-d2and cyclopentene-4,4-d2. The secondary isotope effect has been measured(kH/kD = 1.21 ± 0.03), and the reaction mechanism is interpreted as proceeding through a nitrogen-free intermediate similar to that suggested for the rearrangement of vinylcyclopropane to cyclopentene. At 170° a dramatic change in the product composition occurs, and evidence is presented for a "hot vinylcyclopropane" being produced.

ISSN:0008-4042    

DOI:10.1139/v67-113

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Several heterocycles with fused pyrazole rings were obtained by treatment of thep-nitrophenylhydrazones of several acylated hydrocarbons and thiophene with polyphosphoric acid.

ISSN:0008-4042    

DOI:10.1139/v67-114

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Acid-catalyzed hydrolysis of 19-triphenylmethyloxy-3β-acetoxy-Δ5and -A/B-transsteroids gave the corresponding 19-acetoxy-3β-hydroxy products. In the absence of the 19-triphenylmethyloxy group, transesterification did not occur. Evidence supporting an intramolecular mechanism is presented. It is suggested that the reaction proceeds via an ortho ester VII resulting from the attack of the 19-ether oxygen on the "acetate cation" VI formed by the protonation of the acetate carbonyl.

ISSN:0008-4042    

DOI:10.1139/v67-115

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The polarographic determination of someα-substituted cystines in 0.1 Nhydrochloric acid, with thymol as a maximum suppressor, was investigated. A linear relationship of the diffusion current to the concentration of the compound was observed. The influence of substituent, thymol concentration, and pH on the apparent half-wave potential and shape of the polarograms was determined. The systems were not reversible.Potentiometric titration curves were obtained for theα-substituted cystines.

ISSN:0008-4042    

DOI:10.1139/v67-116

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The generality of the reactionhas been investigated, and examples are given when M = N, X = F or Cl, Y = F, Cl, H, or As(CH3)2, andn = 1, 2, or 3; and when M = As, X = F or Cl, Y = F, Cl, H, or C2H5, andn = 1 or 2. When M = N, Y = OCH3, and X = Cl, the butenoneis obtained; the corresponding reaction with (CH3)2AsH gives only a trace of a butenone. When M = N, Y = C2H5, X = Cl, andn = 1, the simple product is not obtained. The nuclear magnetic resonance spectra of the compounds(Y = H or F) show similar features, notably a shift to high field of the Y resonance when Z is a dialkylamino group.

ISSN:0008-4042    

DOI:10.1139/v67-117

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Three bases isolated fromA. excelsumhave been shown to be yohimbine,O-acetylyohimbine, and a previously unknown alkaloid C22H26N2O4(excelsinine), which is ascribed the structure and stereochemistry shown in formula VI.

ISSN:0008-4042    

DOI:10.1139/v67-118

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The proton spectra of the vinyl groups in a series of 23 substituted styrenes have been analyzed as ABC spin systems. The proton chemical shifts are compared with the previously reported shielding data for the corresponding vinyl carbon nuclei. The series includes 12 meta- and para-substituted examples and 10 ortho-substituted examples. The effects of steric inhibition of conjugation on the vinyl proton parameters for some 2,6-disubstituted derivatives are considered in detail.

ISSN:0008-4042    

DOI:10.1139/v67-119

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The structure of a seventh lignan from the hot-water extractive of western red cedar, which was partially separated in a previous paper, has been determined as 2,3-dihydroxy-2-(3″,4″-dihydroxy-5″-methoxybenzyl)-3-(4′-hydroxy-3′-methoxybenzyl)-butyrolactone (I). This lignan is the fifth member of the thujaplicatin series and is trivially named dihydroxythujaplicatin. Methylation, ethylation, and degradation studies provide proof of structure by comparison with known compounds.

ISSN:0008-4042    

DOI:10.1139/v67-120

出版商:NRC Research Press    

年代:1967

数据来源: NRC