scholarly journals Determination of arrangement of isoprene units in pig liver dolichol by 13C-n.m.r. spectroscopy

1987 ◽  
Vol 243 (2) ◽  
pp. 481-485 ◽  
Author(s):  
Y Tanaka ◽  
H Sato ◽  
A Kageyu ◽  
T Tomita
Keyword(s):  
Chemical Structure ◽  
Reversed Phase ◽  
Hydroxyl Group ◽  
Geometric Isomers ◽  
Model Compounds ◽  
Pig Liver ◽  
Isoprene Unit ◽  
Transfer Measurement ◽  
Slight Amount

The arrangement of isoprene units in pig liver dolichol-18, -19 and -20 was determined by 1H- and 13C-n.m.r. spectroscopies. The alignment of trans and cis isoprene units was found to be in the order: dimethylallyl unit, two trans units, a sequence of 14-16 cis units, and a saturated isoprene unit terminated with a hydroxyl group, which verified the presumed chemical structure of dolichol. The absence of geometric isomers was confirmed. A slight amount of impurity was detected in each reversed-phase h.p.l.c. fraction of dolichol obtained by a conventional method. Detailed assignments of the 13C-n.m.r. spectrum were given for these dolichols by using model compounds and INEPT (insensitive nuclei enhanced by polarization transfer) measurement. The chemical structure of synthetic dolichol-19, which was prepared by the addition of a saturated isoprene unit to the polyprenol-18 isolated from Ginkgo biloba, was confirmed to be identical with that of pig liver dolichol-19.

Determination of Isoprene Unit Structures in Polyisoprene Rubbers

1960 ◽  
Vol 33 (2) ◽  
pp. 587-590 ◽  
Author(s):  
N. G. Kasatkina
Keyword(s):  
Rapid Determination ◽  
Model Compounds ◽  
Isoprene Unit ◽  
Gutta Percha

Abstract Conditions were selected for simple and rapid determination of the percentage of 1,4, 3,4 and 1,2 units in synthetic isoprene rubbers from the curves of the rate of their oxidation by benzoyl hydroperoxide. The content of 1,4, 3,4 and 1,2 units in synthetic isoprene rubbers was determined by comparing the curves of the rate of their oxidation by benzoyl hydroperoxide with the curves of oxidation of model compounds, i.e. limonene and gutta percha.

A comparative technique using as Joint studying to prove structure and determination the Quantitative estimation of organic compound (Irbesartan) as drug in multicomponent tablet form

2019 ◽  
Vol 9 (o3) ◽  
Author(s):  
Imad Tarek Hanoon ◽  
Abed Mohammed Daheir AL-Joubory 2 ◽  
Marwa Mohamed Saied 3
Keyword(s):  
Mobile Phase ◽  
Chemical Structure ◽  
Quantitative Estimation ◽  
Potassium Phosphate ◽  
Hplc Method ◽  
Pharmaceutical Dosage Forms ◽  
Tablet Form ◽  
Rp Hplc ◽  
Percent Recovery

A simple , specific, accurate and precise RP-HPLC method was developed for determination of Irbesartan (IRB) in pharmaceutical dosage forms in tablets products and sachet using symmetry (L 1 ) column at 30°C . The signal was detected at 225 nm. A mobile phase dissolve 0.5 g of buffer potassium phosphate in 100 ml distilled water and adjust pH 2.7 , methanol and acetonitrile at ratio (40 :30 :30 ) . and flow rate 1.2ml/min -1 at pH=7.2 a mobile phase The percent recovery was detected 101 % and the linearity of concentration was 10-50 µg.ml -1 and supported this method by using (FT.I.R.) spectrum method for organic spectrophotometer to prove the chemical structure of this drug and some physical properties . we are obtained the result is identical of other literature . The proposed method was applied successfully for determination of the IRB in tablets products.

Reversed-phase ion-pair chromatography in determination of sinomenine contents in Sinomenium acutum

2010 ◽  
Vol 30 (2) ◽  
pp. 193-195
Author(s):  
Hui WANG ◽  
Qing YE ◽  
Liang ZHAO ◽  
Wen-jun TIAN ◽  
Guo-qing ZHANG
Keyword(s):  
Reversed Phase ◽  
Ion Pair ◽  
Ion Pair Chromatography ◽  
Sinomenium Acutum
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