摘要:

The total acidic products from the performic acid oxidation of the ozonide of methyl oleate formed in methanol may be esterified directly in a few hours with 2,2-dimethoxypropane. The ester concentrations are adequate for the determination of the positional isomers of monoethylenic fatty acids directly from the reaction mixture, using a hydrogen flame ionization gas–liquid chromatography detector. Dimethyl sulfoxide was not required to prevent the breakdown of 2,2-dimethoxypropane under the conditions employed.

ISSN:0008-4042    

DOI:10.1139/v67-232

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Sulfanilamides were found to undergo alkylation with xanthydrol, yielding either mono- or di-xanthenyl derivatives. The site of substitution, common to all sulfanilamides having a freep-amino group, was shown to be theN4-position in the sulfanilamide molecule. Three additional unique reactive sites were observed. Sulfanilamides carrying a thiazole, thiadiazole, or pyridazine substituent in theN1-position were also alkylated on the annular nitrogen atom of the heterocyclic ring, the reaction having occurred from the imido tautomeric form. Sulfisoxazole (IK), on the other hand, reacted from the amido form to give theN1,N4-dixanthenyl derivative. Sulfadimethoxine (Ih) was substituted at carbon, as well as at nitrogen, to yieldN4-xanthenyl-N1-(2,6-dimethoxy-5-(9-xanthenyl)-4-pyrimidyl)sulfanilamide.Sulfanilamides possessing pKavalues of about 5.5 were found to be sufficiently acidic to catalyze their own reaction with xanthydrol, and no external catalyst was necessary. The exceptional ease of formation of the xanthylium ion was postulated to be associated with the resulting stability of this carbonium ion by virtue of its acquired aromatic character.

ISSN:0008-4042    

DOI:10.1139/v67-233

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Egonol, a 2-phenylbenzofuranoid compound of known structure, was obtained from the seed oil ofStyrax americanaLam. The nuclear magnetic resonance spectra of egonol and 3-nitroegonol were examined, and all of the proton signals were assigned. Egonoic acid and egonyl chloroacetate were prepared; their ultraviolet, infrared, and nuclear magnetic resonance spectra confirmed the structure of egonol. The content of egonol in oils may be estimated from the intensity of specified bands in the spectra.

ISSN:0008-4042    

DOI:10.1139/v67-234

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

In the nitration of 4-phenylpyrimidine, the nature of the reaction products is strongly dependent upon the nitrating reagent. Mixed nitric and sulfuric acids yield 4-o- and 4-m-nitrophenylpyrimidines in the ratio 2:3, whereas nitric acid – trifluoroacetic anhydride yields 4-o-, 4-m-, and 4-p-nitrophenylpyrimidines in the ratio 45:29:26, and nitric acid – acetic anhydride yields 2,4-diacetoxy-1,3,5-trinitro-6-phenyl-1,2,3,4-tetrahydropyrimidine.An explanation of these findings involves the possibility of the addition of nitronium ion at the heterocyclic nitrogen, followed in some circumstances by nucleophilic addition.

ISSN:0008-4042    

DOI:10.1139/v67-235

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The use of the Lemieux – von Rudloff technique for the oxidation of the vinyl groups of pimaric(Ib)and sandaracopimaric(IIb)acid methyl esters has been investigated. Although the process leads to the expected C-13 acid V in the case of methyl sandaracopimarate, an unexpected epoxy acid was obtained from methyl pimarate. This product was shown to be the 8β,14β-epoxy-13-α-ketoacid VIIIa, probably arising from an intramolecular process during oxidation of the vinyl group.

ISSN:0008-4042    

DOI:10.1139/v67-236

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Methods have been developed for preparing 17α-deuterio-, 17β-deuterio-, and l7-dideuteriolupanines.The nuclear magnetic resonance and infrared spectra of these provided strongevidence that ring C in the alkaloid is in a boat conformation in solution. Reduction of thesecompounds to the deuterated sparteines confirmed the same geometry for sparteine. In contrast,moilodeuteration of aphylline at C-17 showed that i t had an all-chair conformationin solution. 13β-Hydroxylupanine was shown to have the same conformation as lupaninein solution, but to adopt an all-chair conformation in the solid state.Interpretation of the nuclear magnetic resonance spectra enabled the conformation ofring C of 15-oxosparteine to be assigned. The oxidation and reductions involving C-17 oflupanine have been shown to be highly stereospecific, and an interpretation is given of thedifference betmeen the dehydrogenation of lupanine by mercuric acetate and those byNbromosuccinimideor by the mercuric acetate - ethylenediatninetetraacetic acid complex.It has now been found that the C—H stretching “transbands” in the infrared are evidentwhen only one hydrogen is alpha to the basic nitrogen and in an antiparallel relation to thelone pair of electrons.

ISSN:0008-4042    

DOI:10.1139/v67-237

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The title aminoaldehydes were synthesized byN-acetylation of the corresponding aminoalcohols, Kornblum oxidation to amidoaldehydes, formation of the dimethyl acetals, alkaline amide hydrolysis, and finally acidic acetal hydrolysis. Infrared, ultraviolet, and nuclear magnetic resonance spectral examination indicates that, in solution, the aminoaldehyde hydrochlorides exist in equilibrium withgem-diols or hemiacetals, depending upon the solvent, but that the free bases are reversibly converted into dimeric enamines, to which structures are tentatively assigned. No evidence could be obtained for the presence of monomeric bicyclic carbinolamine tautomers of either the free amines or their salts.

ISSN:0008-4042    

DOI:10.1139/v67-238

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The rate constants are reported for the substitution of acyclic sugar poly-O-acetyl diethyl dithioacetals, poly-O-acetyl diethyl acetals, and poly-O-acetyl dimethyl acetals and for the epimerization of poly-O-acetylS-ethyl monothioacetals when catalyzed by perchloric acid in acetic acid. All the reactions are pseudo first order. Monothioacetals substitute faster than oxygen acetals, and oxygen acetals substitute faster than sulfur acetals. A group bonded to C1of these acyclic sugar derivatives is substituted faster than when the group is bonded to C1of poly-O-acetyl pyranose derivatives.

ISSN:0008-4042    

DOI:10.1139/v67-239

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The rate constants for the inversion and for the14C-acetoxy exchange of the diastereomeric 1,2,3,4,5-penta-O-acetylS-ethyl monothioacetals show that the substitution is not anchimerically assisted by the C2-acetoxy group. The substitution of acyclic poly-O-acetyl sugar monoacetals is best explained by the formation of the acyclic intermediate(X = S or O) in the rate-determining step.

ISSN:0008-4042    

DOI:10.1139/v67-240

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The proton magnetic resonance spectrum of the tetrahydropyranyl ether of 2,2,2-trifluoroethanol has been measured in several solvents and at different temperatures. Analysis of the ABX3pattern produced by the trifluoroethyl group revealed a unique feature. Under all conditions, it was found that the vicinal coupling constantsJAXandJBXhad different magnitudes. This non-equivalence is interpreted as evidence that the C—HAand C—HBbonds of the trifluoroethyl group differ electronically. A possible relation between this finding and the anomeric effect is discussed. In contrast to the above results, the tetrahydropyranyl ether of ethanol showed equal vicinal proton–proton coupling constants in the ethyl group.

ISSN:0008-4042    

DOI:10.1139/v67-241

出版商:NRC Research Press    

年代:1967

数据来源: NRC