Study on the correspondence of color change with polyenyl cation formation of cholesterol in strong acids.

Niiya, Tokihiro; Goto, Yoshinobu; Ono, Yoshio; Ueda, Yo

doi:10.1248/cpb.28.1747

Cited by 7 publications

(9 citation statements)

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“…Cholesterol dimers have been proposed as the initial species in colorimetric reactions [11,15] [9,[12][13][14], the selectivity of the LB reaction ( Fig. 1), the UV behavior, and the reaction kinetics (first order in cholesterol) indicate this to be a very minor pathway.…”

Section: Discussionmentioning

confidence: 99%

“…The methanolic supernatant was evaporated to a residue (5.3 g), which was chromatographed on a 200-g C 18 column (50-100% methanol in water) to give, in order of elution, 15,18,12,17,19,20,13,14, and 16. Compounds 12-14 crystallized as colorless needles, but most other steroids were eluted as mixtures that were further purified by HPLC or TLC on C 18 media.…”

Section: Sterols Produced By Lb Reaction Bmentioning

confidence: 99%

“…Very few LB products have been characterized beyond UV and combustion analyses, and no polar intermediates have been reported apart from steryl sulfates and perchlorates. Investigators variously postulate cholesterol dimers [11,15], cholestadienes [9,12,13], or epicholesterol derivatives [9] as pivotal intermediates without any evidence of their quantitative importance. As a result, the behavior of cholesterol in strongly acidic solution is still poorly understood.…”

Section: Introductionmentioning

confidence: 99%

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The Liebermann–Burchard Reaction: Sulfonation, Desaturation, and Rearrangment of Cholesterol in Acid

Xiong

Wilson

Pang

2007

Lipids

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In the Liebermann-Burchard (LB) colorimetric assay, treatment of cholesterol with sulfuric acid, acetic anhydride, and acetic acid elicits a blue color. We studied the reactivity of cholesterol under LB conditions and provide definitive NMR characterization for approximately 20 products, whose structure and distribution suggest the following mechanistic picture. The major reaction pathways do not involve cholestadienes, i-steroids, or cholesterol dimers, as proposed previously. Instead, cholesterol and its acetate and sulfate derivatives undergo sulfonation at a variety of positions, often with skeletal rearrangements. Elimination of an SO(3)H group as H(2)SO(3) generates a new double bond. Repetition of this desaturation process leads to polyenes and ultimately to aromatic steroids. Linearly conjugated polyene cations can appear blue but form too slowly to account for the LB color response, whose chemical origin remains unidentified. Nevertheless, the classical polyene cation model is not excluded for Salkowski conditions (sulfuric acid), which immediately generate considerable amounts of cholesta-3,5-diene. Some rearrangements of cholesterol in H(2)SO(4) resemble the diagenesis pathways of sterols and may furnish useful lipid biomarkers for characterizing geological systems.

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Section: Discussionmentioning

confidence: 99%

Section: Sterols Produced By Lb Reaction Bmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Liebermann–Burchard Reaction: Sulfonation, Desaturation, and Rearrangment of Cholesterol in Acid

Xiong

Wilson

Pang

2007

Lipids

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“…The baseline (i 0 ) is recorded for (chloroform-TBAP + acetic anhydride + H 2 SO 4 ) solution and when adding the cholesterol, the oxidation current increases rapidly (i 1 ) ( Figure 2 , blue line) and the response (Δi ox ) is depending on the cholesterol concentration. Since the Liebermann–Burchard reaction is a colorimetric assay [ 31 , 32 , 33 ], we concomitantly see the instant change of solution color.…”

Section: Resultsmentioning

confidence: 99%

Innovative Non-Enzymatic Electrochemical Quantification of Cholesterol

Carp¹,

Pinteala²,

Arvinte³

2022

Sensors

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The use of the Liebermann–Burchard reaction in this study has been explored in the development of a simple, reliable, and robust quantitative electrochemical method to assay cholesterol, and hence provide a good alternative to colorimetric methods. The optimization of batch mode operation for electrochemical oxidation of cholesterol in the Liebermann–Burchard reagents included the applied potential and acidic volume. Tested using chronoamperometry, the developed method showed a high sensitivity (14.959 μA mM−1) and low detection limit (19.78 nM) over a 0.025–3 mM concentration range, with remarkable linearity (R2  =  0.999), proving an analytical performance either higher or comparable to most of the cholesterol sensors discussed in literature. The influence of possible interfering bioactive agents, namely, glucose, uric acid, ascorbic acid, KCl and NaCl, has been evaluated with no or negligible effects on the measurement of cholesterol. Our study was directed at finding a new approach to chemical processing arising from the use of external potential as an additional level of control for chemical reactions and the transfer of electrons between surfaces and molecules. Finally, the optimized method was successfully applied for the determination of cholesterol content in real blood samples.

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“…6 A standard colour test for the presence of cholesterol is the formation of a green colour in concentrated sulphuric acid, and this was shown to be due to a polyenyl steroidal dimer carbocation. [7][8][9] Many dimeric and oligomeric steroids exhibit interesting micellular, detergent and liquid crystal behaviour. 10,11 Most of the steroidal dimmers are also well-known for their pharmacological activity.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of steroidal dimers: Selective amine catalysed steroidal dimerization

2011

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Some new dimeric steroids namely cholest-5-en-3-spiro-[6 α,5 -oxa]-5 α-cholest-3 -one (2), cholest-5-en-7-spiro-[4 α,5 -oxa]-5 α-cholest-7 -one (4a) and 3β-substitutedcholest-5-en-7-spiro-[4 α,5 -oxa]-3 β-substituted-5 α-cholestan-7 -ones (4b, c) are synthesized starting from cholest-5-en-3-one (1), cholest-5-en-7-one (3a) and 3β-substituted-cholest-5-en-7-ones (3b, c) respectively by using DMAP and xylene. All the synthesized compounds were characterized by using IR, MS and 1 H, 13 C NMR spectral and elemental analysis.

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Study on the correspondence of color change with polyenyl cation formation of cholesterol in strong acids.

Cited by 7 publications

References 0 publications

The Liebermann–Burchard Reaction: Sulfonation, Desaturation, and Rearrangment of Cholesterol in Acid

The Liebermann–Burchard Reaction: Sulfonation, Desaturation, and Rearrangment of Cholesterol in Acid

Innovative Non-Enzymatic Electrochemical Quantification of Cholesterol

Synthesis of steroidal dimers: Selective amine catalysed steroidal dimerization

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