摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v67-152

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The Friedel–Crafts acetylation of methyl 2-pyrrolecarboxylate, 2-pyrrolecarboxaldehyde, and 2-pyrrolecarbonitrile was investigated and found to give 4-substitution mainly or exclusively. The 4-acetyl-2-substituted products were converted into the 4-acetyl-2-acid, and then into 3-acetylpyrrole (methyl 3-pyrryl ketone). The Friedel–Crafts isopropylation and the bromination of both methyl 3-pyrrolecarboxylate and 3-acetylpyrrole were found to produce almost exclusively 5-substituted products.

ISSN:0008-4042    

DOI:10.1139/v67-153

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

A HammettH0acidity function based on the protonation of 17 diphenylamines in 20 volume % ethanol – aqueous sulfuric acid has been established. TheH0value for the most acidic solution studied (11.2 Msulfuric acid) is −6.97. This acidity function differs from that based on the protonation of azobenzenes in the same solvent system; the latter diverges to more negativeH0values as the sulfuric acid concentration increases.Thevalues for the protonation of the diphenylamines vary from +1.36 for 4-methoxy-diphenylamine to − 6.21 for 4,4′-dinitrodiphenylamine. A plot ofversus the Hammettσconstants for five monosubstituted diphenylamines yields aρvalue of +3.36. Thevalues for 4-methoxy-, 4-methyl-, 4-methylsulfonyl-, and 4-nitro-diphenylamine are all less (more negative) than expected from the Hammett substituent constants. The substituent effects on the basicities of aniline and diphenylamine are the same.The basicities of several nitro-substituted diphenylamines appear to vary regularly, and do not reflect the presence of a strong interaction between the nitro group and sulfuric acid.

ISSN:0008-4042    

DOI:10.1139/v67-154

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

AnH−acidity function based on the ionization of 24 substituted anilines and diphenylamines has been established in the system dimethyl sulfoxide – water – tetramethylammonium hydroxide. TheH−of a 0.011Msolution of tetramethylammonium hydroxide ranges from 12 in water to 26.2 in 99.6 mole % dimethyl sulfoxide – water, an increase in basicity of 14 powers of 10. The increase in basicity is due to the increased activity of the hydroxide ion brought about by the reduction in its solvation in the poor anion-solvating solvent dimethyl sulfoxide, and indicates the extensive solvation enjoyed by the hydroxide ion in water.The pKHAvalues of the indicator acids vary from 13.9 for 2,4-dinitrodiphenylamine to 25.6 for 3-chloroaniline. From a plot of logKHAversus the Hammett substituent constants (σ) for six monosubstituted diphenylamines, aρvalue of 4.07 is found. Similar results are obtained for the anilines. The acidities of all the substituted diphenylamines do not follow the above-mentioned correlation with the Hammett σ constants; the pKHAvalues of 4-amino-, 4-methoxy-, 4-methylsulfonyl-, and 4-nitro-diphenylamine are all less than expected from the Hammett σ constants for the substituents in these compounds. The 4-nitro substituent exerts a particularly large acid-strengthening effect on the acidities of aniline and diphenylamine, the decreases in pKHAbeing approximately 8.4 and 6.8 pK units, respectively. An exalted substituent constant of +1.65 forp-NO2is needed to account for the acidity ofp-nitro-diphenylamine.

ISSN:0008-4042    

DOI:10.1139/v67-155

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The acidities of a series of anilines and diphenylamines are compared with their basicities. A plot of the acidity versus the basicity(pKHAon ordinate versus) of nine diphenylamines yields a straight line with a slope of 1.30. In a similar plot for 33 substituted anilines and diphenylamines, two types of behavior are observed. Those anilines and diphenylamines without an ortho- or para-nitro group fall about the line with a slope of 1.30, whereas those amines with at least one nitro group in the ortho or para position fall on a different, curved line with a slope of less than unity. The first conjugating nitro group thus has an anomalously large effect on the acidity, but not on the basicity, of aromatic amines. The reasons for this are discussed.An estimate of 33.5 is obtained for the pKHAof ammonia.

ISSN:0008-4042    

DOI:10.1139/v67-156

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

It has been shown by nuclear magnetic resonance spectral analysis that 4a,8a-dimethoxy-4a,8a-dihydro-1,4-benzodioxan (I) and 4a,8a-dimethoxy-4a,5,6,7,8,8a-hexahydro-1,4-benzo-dioxan (II) possess thetransstereochemistry at the ring junction.

ISSN:0008-4042    

DOI:10.1139/v67-157

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Dimerization of conjugated cyclodienes in the presence of lithium–naphthalene gave new dimers. 1-(2′-Cycloocten-1′-yl)-2-cyclooctene was prepared from 1,3-cyclooctadiene, 1,4-dicyclohexyliden-n-butane from 1-vinyl-1-cyclohexene, and a terpene dimer from α-phellandrene.

ISSN:0008-4042    

DOI:10.1139/v67-158

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Thiourea and monosubstituted andsym-disubstituted alkyl and aryl thioureas react with dimethyl acetylenedicarboxylate to give, in a good yield, 2,3-dihydro-1,3-thiazin-4-ones, and not thiazolidinones as has been claimed previously. Monosubstituted thioureas react to give 2-alkylimino compounds exclusively. The adducts can be hydrogenated to give the perhydro-thiazinones. High-resolution mass spectrometry of the dihydro- and perhydro-thiazinones shows many common fragmentations typical of the ring system and often characteristic of the type and position of substituents, which may be used to identify such compounds readily.

ISSN:0008-4042    

DOI:10.1139/v67-159

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Substituted thiosemicarbazides react with dimethyl acetylenedicarboxylate to give 3-amino-2,3-dihydrothiazin-4-ones. Confirmation of the structures is provided by catalytic hydrogenation and by characteristic mass spectral fragmentations. 4-Substituted thiosemicarbazides react with methyl propiolate in the same way as monosubstituted hydrazines and hydrazides to give hydrazones, whereas 1-substituted thiosemicarbazides undergo smooth removal of the sulfur with the production of an equal mixture ofcis–transandcis–cisdimethyl-β-thiodiacrylic esters. Bicyclic heterocyclic structures are formed by reaction of dimethyl acetylenedicarboxylate with imidazolidone thione and with 5,5-dimethyl-2-thiohydantoin. Substituted guanidines react with dimethyl acetylenedicarboxylate in an analogous fashion, yielding substituted 2,3-dihydrodiazinones. The high-resolution mass spectra of the latter show many similarities to the spectra of the sulfur analogues. Thioamides, despite previous claims to the contrary, react with dimethyl acetylenedicarboxylate to give thioethers of fumarate ester or 1,3-thiazin-4-ones. In contrast, thioamides react with methyl propiolate to give an equal mixture ofcis–transandcis–cisdimethyl-β-thiodiacrylic esters.

ISSN:0008-4042    

DOI:10.1139/v67-160

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The root ofA. septentrionaleKoelle has been found to contain a number of alkaloids, seven of which have been isolated and characterized. The major alkaloid is the previously known lappaconitine. The minor bases, except alkaloid D, appear to be new. Of these, the main one, alkaloid A (C43H59O12N3), is a double ester, since it consists of an alkamine esterified with a methyl ester ofN-succinoylanthranilic acid. The other minor bases are alkaloid B (C17H25O2N), alkaloid C (C19H27O3N), alkaloid D (C30H42O7N2) which is deacetyllappaconitine, alkaloid E (C37H54O7N) containing no ester group, and alkaloid F (C19H29O6N). No trace of the previously reported cynoctonine and septentrionaline was found.

ISSN:0008-4042    

DOI:10.1139/v67-161

出版商:NRC Research Press    

年代:1967

数据来源: NRC