scholarly journals An octadecatrienoic acid from Lamium purpureum L. seed oil containing 5,6-allenic and trans-16-olefinic unsaturation

1967 ◽  
Vol 105 (3) ◽  
pp. 1245-1249 ◽  
Author(s):  
K. L. Mikolajczak ◽  
Mary F. Rogers ◽  
C. R. Smith ◽  
I. A. Wolff
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Methyl Ester ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Seed Oil ◽  
Trienoic Acid ◽  
Resonance Spectroscopy ◽  
Partial Reduction

1. Lamium purpureum L. (Labiatae) seed oil contains 16% of a new acid characterized as (−)-octadeca-5,6-trans-16-trienoic acid (proposed trivial name ‘lamenallenic acid’) (Ia). The acid was isolated as its methyl ester by countercurrent distribution by using a combination of recycle–single withdrawal techniques. Methyl lamenallenate (Ib) is strongly laevorotatory. 2. The structure was established by infrared spectroscopy, nuclear-magnetic-resonance spectroscopy, quantitative hydrogenation and oxidative cleavage data of the original acid and of hydrazine partial reduction products. 3. Other unsaturated esters identified by their cleavage products were oleate, linoleate and linolenate. 4. A very small amount (less than 1%) of methyl laballenate [(−)-methyl octadeca-5,6-dienoate] was also isolated and identified.

Fluorination of sulfur-containing amino acids: Reaction of xenon difluoride with cysteine derivatives

1990 ◽  
Vol 68 (3) ◽  
pp. 477-479 ◽  
Author(s):  
Xiaoling Huang ◽  
Barry J. Blackburn ◽  
Steve C. F. Au-Yeung ◽  
Alexander F. Janzen
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Methyl Ester ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Xenon Difluoride ◽  
Nitrophenyl Ester ◽  
Sulfur Containing

The reaction of XeF2 with cysteine derivatives RSCH2CH(NHR)COOR, i.e., S-benzyl-N-trifluoroacetyl-L-cysteine methyl ester, S-benzyl-N-carbobenzoxy-L-cysteine p-nitrophenyl ester, and S-methyl-N-trifluoroacetyl-L-cysteine methyl ester is described. The fluorinated products PhCHFSCH2CH(NHR)COOR, PhCH2SCHFCH(NHR)COOR, and FCH2SCH2CH(NHR)COOR were identified by 1H and 19F nuclear magnetic resonance spectroscopy. PhCH2SCHFCH(NHR)COOR loses HF within 24 hours to give Z- and E-PhCH2SCH=C(NHR)COOR. If the reaction with XeF2 is carried out in the presence of moisture the sulfoxide RS(O)CH2CH(NHR)COOR and sulfone RSO2CH2CH(NHR)COOR are produced. Keywords: fluorination, XeF2, amino acids, cysteine.

scholarly journals Optimization of the extraction of carrageenan from Kappaphycus alvarezii using response surface methodology

2012 ◽  
Vol 32 (4) ◽  
pp. 812-818 ◽  
Author(s):  
Vanessa Webber ◽  
Sabrina Matos de Carvalho ◽  
Paulo José Ogliari ◽  
Leila Hayashi ◽  
Pedro Luiz Manique Barreto
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Response Surface Methodology ◽  
Infrared Spectroscopy ◽  
Chemical Composition ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Gel Strength ◽  
Resonance Spectroscopy ◽  
Extraction Temperature

This study aims to optimize an alternative method of extraction of carrageenan without previous alkaline treatment and ethanol precipitation using Response Surface Methodology (RSM). In order to introduce an innovation in the isolation step, atomization drying was used reducing the time for obtaining dry carrageenan powder. The effects of extraction time and temperature on yield, gel strength, and viscosity were evaluated. Furthermore, the extracted material was submitted to structural analysis, by infrared spectroscopy and nuclear magnetic resonance spectroscopy (¹H-NMR), and chemical composition analysis. Results showed that the generated regression models adequately explained the data variation. Carrageenan yield and gel viscosity were influenced only by the extraction temperature. However, gel strength was influenced by both, extraction time and extraction temperature. Optimal extraction conditions were 74 ºC and 4 hours. In these conditions, the carrageenan extract properties determined by the polynomial model were 31.17%, 158.27 g.cm-2, and 29.5 cP for yield, gel strength, and viscosity, respectively, while under the experimental conditions they were 35.8 ± 4.68%, 112.50 ± 4.96 g.cm-2, and 16.01 ± 1.03 cP, respectively. The chemical composition, nuclear magnetic resonance spectroscopy, and infrared spectroscopy analyses showed that the crude carrageenan extracted is composed mainly of κ-carrageenan.

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