摘要:

The structure of kerlinic acid, aneo-clerodane diterpenoid isolated fromSalviakeerlii(Labiatae), was deduced from spectral data and chemical correlation with melisodoric acid.

ISSN:0008-4042    

DOI:10.1139/v87-445

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

15N nuclear magnetic resonance spectra of adenosine derivatives were taken at the natural abundance level, and the reflection of structural modifications on the spectra was considered on the basis of the electronic behaviour of the molecules.

ISSN:0008-4042    

DOI:10.1139/v87-446

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Free radical additions of hydrogen donors of type ZH to δ-unsaturated organic peroxides give 5- or 6-membered cyclic ethers in yields varying from 40 to 70%, depending on the substitution of the double bond. [Journal translation]

ISSN:0008-4042    

DOI:10.1139/v87-447

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

This paper describes the chemical preparation of the 10,11-dihydroxyquinidines, some of the metabolites of quinidine. The 10(R) and 10(S) isomers have been separated using the isopropylidene derivatives. The physical characteristics of each of these isomers have been determined and their respective structures have also been determined using1H nuclear magnetic resonance at 400 MHz. On the basis of an X-ray diffraction structure determination, it has been shown that the main product, melting point 239 °C, is the 10(R) isomer. This product crystallizes with one molecule of water in the orthorhombic system witha = 8.756(2),b = 11.499(7), andc = 19.123(5) Å and space groupP212121. The structure has been refined to a final value ofR = 0.040 for 2039 observed reflections. [Journal translation]

ISSN:0008-4042    

DOI:10.1139/v87-448

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Deuterium isotope effects on the31P shielding constants and spin–spin coupling constants in the isoelectronic series, PH2−, PH3, PH4+, are examined. Also, deuterium isotope effects on the nuclear magnetic resonance parameters of SnH3−are examined and compared with our earlier results on SnH4and SnH3+. The experimental results are analyzed using the models of Jameson and Osten. In each isoelectronic series it is found that the isotope effects on the heavy atom chemical shifts are largest for the negatively charged ions and essentially zero for the positively charged ions, as predicted by recent molecular orbital calculations. The primary isotope effects onJ(A,H) are positive for all species containing lone-pair electrons, otherwise Δp1J(A,H) is negative. The primary and secondary isotope effects onJ(Sn,H) in the SnH3−ion are the largest reported to date.

ISSN:0008-4042    

DOI:10.1139/v87-449

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Activation of a representative 3,5-diaryl-1,3,4-thiadiazole-2-thione by thione S-methylation gives a cation that is readily susceptible to nucleophilic substitution. Reactions with diethyl malonate, ethyl acetoacetate, acetylacetone, cyclopentan-1,3-dione, or 3-ethylrhodanine under basic conditions lead to β,β-disubstituted methine bases and (or) β-substituted methine bases in cases where deacetylation occurs under the reaction conditions. This cation and the 2-alkyl-3,5-diaryl-1,3,4-thiadiazolium cation are convenient sources of a series of neutral and cationic dyes containing the 1,3,4-thiadiazole ring system.

ISSN:0008-4042    

DOI:10.1139/v87-450

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

1,1-Dimorpholinoethene and 1,1-dipiperidinoethene condense with such compounds as malononitrile, ethyl cyanoacetate, cyanoacetamide, and diethyl malonate to give the corresponding β,β-disubstituted enamine, a molecule of morpholine or piperidine being eliminated in the process. Similar reactions with acetylacetone and ethyl acetoacetate proceed with loss of the acetyl group to give the β-substituted enamine. 1,1-Dipiperidinoethene and nitromethane give the β-nitroenamine. Secondary processes of either hydrolysis or further Michael addition and elimination are noted in condensations of 1,1-dimorpholinoethene or 1,1-dipiperidinoethene with cyanoacetamide under more basic conditions.1,1-Dipiperidinoethene is arylated at the 2-position by 2,4-dinitrochlorobenzene.

ISSN:0008-4042    

DOI:10.1139/v87-451

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Pig liver esterase (PLE) catalyzed hydrolysis of racemic piperidine esters proceeds enantioselectively to give product acids and recovered esters in 0–47% enantiomeric excess.

ISSN:0008-4042    

DOI:10.1139/v87-452

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Photolysis of β-pinene and dodecamethylhexasilane (2) followed by methanol quenching gave the allylsilane5and the methoxysilane6. The intermediacy of the silirane7was proposed. Photolysis of α-pinene and2gave6only. The formation of another silirane15as intermediate was verified by deuterium labelling experiment. The potential of silylene chemistry in organic synthesis was examined.

ISSN:0008-4042    

DOI:10.1139/v87-453

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The δ-lactone of 3,5-dihydroxydecanoic acid was synthesized from methyl-3-oxooctanoate by utilizing its baker's yeast reduction.

ISSN:0008-4042    

DOI:10.1139/v87-454

出版商:NRC Research Press    

年代:1987

数据来源: NRC