Preparation of cis- and trans-2,5-dimethoxytetrahydropyran and cis- and trans-2,5-dimethoxy-6-methyltetrahydropyran

1970 ◽  
Vol 48 (15) ◽  
pp. 2334-2340 ◽  
Author(s):  
R. M. Srivastava ◽  
R. K. Brown
Keyword(s):  
Liquid Chromatography ◽  
Palladium Catalyst ◽  
Gas Liquid Chromatography ◽  
Subsequent Reduction ◽  
Subsequent Oxidation ◽  
Cis And Trans

Hydroboration and subsequent oxidation of 2-methoxy-3,4-dihydro-2H-pyran gave a 1:2 mixture of cis- and trans-5-hydroxy-2-methoxytetrahydropyran (2). From the methylated product 4, trans-2,5-dimethoxytetrahydropyran could be obtained by gas–liquid chromatography. The cis-2,5-dimethoxy-tetrahydropyran (8) was obtained by conversion of 4 to 3-methoxy-3,4-dihydro-2H-pyran (6) which upon bromomethoxylation and subsequent reduction with palladium catalyst gave 8.Both cis- and trans-2,5-dimethoxy-6-methyltetrahydropyran (11) were obtained by hydroboration and oxidation of 2-methoxy-6-methyl-3,4-dihydro-2H-pyran (9) followed by methylation of the resulting product.

Differential solution behavior of cis and trans esters of 4-substituted tert-butylcyclohexanes as studied by gas-liquid chromatography

1968 ◽  
Vol 40 (4) ◽  
pp. 727-735 ◽  
Author(s):  
Barry L. Karger ◽  
Robert L. Stern ◽  
Joseph F. Zannucci
Keyword(s):  
Liquid Chromatography ◽  
Gas Liquid Chromatography ◽  
Solution Behavior ◽  
Cis And Trans

Reliable separation of cis and trans fatty acids by gas liquid chromatography on glass capillary columns

1975 ◽  
Vol 8 (9) ◽  
pp. 507-510 ◽  
Author(s):  
H. Jaeger ◽  
H. -U. Klör ◽  
G. Blos ◽  
H. Ditschuneit
Keyword(s):  
Fatty Acids ◽  
Liquid Chromatography ◽  
Trans Fatty Acids ◽  
Capillary Columns ◽  
Gas Liquid Chromatography ◽  
Glass Capillary ◽  
Glass Capillary Columns ◽  
Cis And Trans

Analysis of C18:1 cis and trans fatty acid isomers by the combination of gas-liquid chromatography of 4,4-dimethyloxazoline derivatives and methyl esters

1998 ◽  
Vol 75 (8) ◽  
pp. 977-985 ◽  
Author(s):  
Antti Aro ◽  
Truus Kosmeijer-Schuil ◽  
Peter van de Bovenkamp ◽  
Paul Hulshof ◽  
Peter Zock ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Fatty Acid ◽  
Trans Fatty Acid ◽  
Methyl Esters ◽  
Gas Liquid Chromatography ◽  
Trans Fatty Acid Isomers ◽  
Cis And Trans

Hydroboration of 1,4-diallylpiperazine

1985 ◽  
Vol 50 (10) ◽  
pp. 2275-2283 ◽  
Author(s):  
Stanislav Kafka ◽  
Miloslav Ferles
Keyword(s):  
Mass Spectrometry ◽  
Hydrogen Peroxide ◽  
Liquid Chromatography ◽  
Hydrochloric Acid ◽  
Sodium Borohydride ◽  
Gas Liquid Chromatography ◽  
Alkaline Hydrogen Peroxide ◽  
Subsequent Oxidation

Hydroboration of 1,4-diallylpiperazine (I) with triethylamine-borane afforded 5,8-diaza-1,9-diboradispiro[4,2,4,2]tetradecane (II). 1,4-Diallylpiperazine dihydrochloride reacted with sodium borohydride to give 1,4-diallylpiperazine-diborane (V). Ethanolysis of II furnished 1,4-bis(3-diethoxyborylpropyl)piperazine (IV). The products of hydroboration of I were subjected to hydrolysis with hydrochloric acid and subsequent oxidation with alkaline hydrogen peroxide and the obtained mixtures were analysed by gas-liquid chromatography and mass spectrometry.

Chemical Confirmation of Diethylstilbestrol Residues in Beef Livers

1976 ◽  
Vol 59 (4) ◽  
pp. 817-820
Author(s):  
John Joseph Ryan ◽  
Jean-Claude Pilon
Keyword(s):  
Liquid Chromatography ◽  
Electron Capture ◽  
Room Temperature ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Beef Liver ◽  
Simple Chemical ◽  
Chemical Technique ◽  
Cis And Trans

Abstract A simple chemical technique was developed to confirm the presence of diethylstilbestrol (DES) residues in beef tissues at 2 ppb. The DES-trifluoroacetate (TFA) from the previously published method is hydrolyzed in water-methanol at 55°C for 20 min to free DES which is then extracted into benzene. Trimethylamine and a small amount of heptafluorobutyric (HFB) anhydride are added to effect the smooth conversion of DES to its di-HFB at either room temperature or 60°C. DES-HFB is determined by gas-liquid chromatography with electron capture detection on a 6′ × 4 mm id column of 3% OV-210 at 190°C. This procedure yields 2 peaks for DES-HFB (retention times 2.7 and 4.8 min for the cis and trans, respectively) which are resolved from the 2 DES-TFA peaks (retention times 2.3 and 3.3 min for cis and trans, respectively). The sensitivity of detection of DES-HFB is increased by a factor of 4–5 over that for DES-TFA. This chemical technique was successfully applied to purified extracts of beef liver fortified with DES at 2–10 ppb with recoveries from 60 to 110%.

scholarly journals Separation and Determination of cis- and trans- dl-Chrysanthemumic Acid by Gas Liquid Chromatography

1969 ◽  
Vol 33 (7) ◽  
pp. 1095-1096 ◽  
Author(s):  
Junshi MIYAMOTO ◽  
Yoshishige SATO ◽  
Keiko AWANO
Keyword(s):  
Liquid Chromatography ◽  
Gas Liquid Chromatography ◽  
Cis And Trans

GAS–LIQUID CHROMATOGRAPHY OF TERPENES: XV. THE VOLATILE OIL OF MENTHA ARVENSIS VAR. GLABRATA RAY

1966 ◽  
Vol 44 (17) ◽  
pp. 2015-2022 ◽  
Author(s):  
E. von Rudloff ◽  
F. W. Hefendehl
Keyword(s):  
Liquid Chromatography ◽  
Maximum Yield ◽  
Volatile Oil ◽  
Quantitative Composition ◽  
Gas Liquid Chromatography ◽  
Oil Composition ◽  
Mentha Arvensis ◽  
Autoxidation Product ◽  
The North ◽  
Cis And Trans

The volatile oil of the North American wild mint (Menthaarvensis L. var. glabrata) was found to consist mainly of d-pulegone (80–90%) and smaller amounts of α-pinene, β-pinene, sabinene, limonene, 1,8-cineole, 1-octen-3-ol, menthone, isomenthone, piperitone, cis- and trans-pulegone oxide, and piperitenone. Trace amounts of γ-terpinene, menthofuran, β-caryophyllene, and ε-, δ-, and γ-cadinene were also isolated, and camphene, p-cymene, terpinolene, sabinene hydrate, isopulegone or its stereoisomer, β-elemene, and α-terpineol were tentatively identified. A labile autoxidation product of pulegone was also detected.A study of the seasonal variations in the oil composition showed that significant changes in the quantitative composition occurred only in very young plants. The maximum yield of oil was obtained at the start of flowering. Practically no variation in the composition of the oil was recorded for plants from different localities.

Cyclodextrin as a tool for separating cis- and trans-decalin by gas—liquid chromatography

1986 ◽  
Vol 351 ◽  
pp. 512-517 ◽  
Author(s):  
Tomasz Kościelski ◽  
Danuta Sybilska ◽  
Janusz Lipkowski ◽  
Anna Miediokritskaja
Keyword(s):  
Liquid Chromatography ◽  
Gas Liquid Chromatography ◽  
Cis And Trans
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