Related Experiment Video
Updated: May 5, 2026
08:31
Optimized Griess Reaction for UV-Vis and Naked-eye Determination of Anti-malarial Primaquine
Published on: October 11, 2019
9.0K
Rapid aromatic hydrogen exchange in the antimalarial primaquine
1The Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, University, MS, 38677.
Pharmaceutical Research
|November 27, 2013
Summary
Primaquine, an antimalarial drug, rapidly exchanges protons on its aromatic ring. This fast proton exchange, especially at C-5, may explain its biological activity.
Area of Science:
- Medicinal Chemistry
- Organic Chemistry
- Parasitology
Background:
- Primaquine is an essential 8-aminoquinoline antimalarial drug.
- Understanding its chemical properties is crucial for drug development and efficacy.
Purpose of the Study:
- To investigate the proton exchange rates of primaquine.
- To determine if rapid proton exchange correlates with biological activity.
Main Methods:
- Proton nuclear magnetic resonance (NMR) spectroscopy was used.
- Experiments were conducted across a range of pH values.
Main Results:
- Primaquine exhibits unexpectedly rapid aromatic proton exchange.
- At pH < 4, C-5 proton exchange was too fast to measure.
- At pH 6-6.5, the half-time for exchange was 4-5 minutes.
Conclusions:
- The rapid proton exchange of primaquine is a significant chemical characteristic.
- This property may offer insights into the drug's mechanism of action and antimalarial activity.
Related Concept Videos
01:19Phase I Reactions: Oxidation of Aliphatic and Aromatic Carbon-Containing Systems
953
Phase I biotransformation reactions are integral to drug metabolism, predominantly involving oxidative, reductive, and hydrolytic transformations. Chief among these are oxidative reactions, which enhance the hydrophilicity of xenobiotics and introduce polar functional groups to facilitate their elimination from the body.
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...
953
01:11Nucleophilic Aromatic Substitution: Elimination–Addition
2.9K
Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is...
2.9K
01:16Electrophilic Aromatic Substitution: Overview
13.0K
In an electrophilic aromatic substitution reaction, an electrophile substitutes for a hydrogen of an aromatic compound.
13.0K
01:17Drug Metabolism: Phase I Reactions
5.1K
A phase I reaction is a biochemical process that introduces a functionally reactive polar group to a substance. This transformation predominantly occurs in the liver, facilitated by the cytochrome P450 system of hemoproteins situated in the lipophilic endoplasmic reticulum of cells. The metabolite generated through this process can have varying polarities. If it is sufficiently polar, it can be easily excreted in the urine due to its water compatibility. However, if the metabolite is nonpolar,...
5.1K
01:19Phase II Reactions: Miscellaneous Conjugation Reactions
477
Phase II biotransformations are detoxification mechanisms that conjugate xenobiotics with endogenous substances, neutralizing their toxicity.
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
477
01:15Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
9.5K
Chlorination and bromination are important classes of electrophilic aromatic substitutions, where benzene reacts with chlorine or bromine in the presence of a Lewis acid catalyst to give halogenated substitution products. A Lewis acid such as aluminium chloride or ferric chloride catalyzes the chlorination, and ferric bromide catalyzes the bromination reactions. During the bromination of alkenes, bromine polarizes and becomes electrophilic. However, in the bromination of benzene, the bromine...
9.5K