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Introduction
Pseudoephedrine (PSE) (CAS № 90-82-4) is a substituted amphetamine, one of the isomers of ephedrine. It was first characterized in 1889 by the German chemists Ladenburg and Oelschlägel, who used a sample that had been isolated from Ephedra vulgaris. Used for relieving nasal congestion associated with colds, flu, and allergic rhinitis. Beyond its primary use, the compound’s structural similarity to ephedrine, it is used in various chemical reactions.
Its molecular structure determines the physical, chemical reactions of the compound and the chiral nature of pseudoephedrine, leading to its interaction with biological targets, influencing its pharmacodynamics and pharmacokinetics, as well as the synthesis of other pharmaceutical drugs and the production of methamphetamine.
The purpose of this article is to provide information about physical properties of pseudoephedrine (CAS № 90-82-4): density, solubility, melting and boiling points, chemical reactions, applications, health effects and safety precautions.

Physical and Chemical Properties of Pseudoephedrine
Pseudoephedrine, (PSE) (CAS № 90-82-4), is a substituted amphetamine with the chemical formula C10H15NO and a molecular weight 165.23 g/mol. This is colorless needle crystals or white crystalline powder, with a slight specific odor. Its density is 1.118 g/cm3. Solubility of pseudoephedrine: water 2.0 g/mL (at 25°C), chloroform 0.011 g/mL (at 25°C), ethanol 0.278 g/mL (at 25°C). Pseudoephedrine have boiling point about 130°C (at 16 Torr). Melting point of pseudoephedrine is 118-120°C.
Pseudoephedrine (CAS № 90-82-4) is characterized by its stereochemistry. It exists as a diastereomer of ephedrine, the main difference being the configuration of the hydroxyl group and the methyl attached to the nitrogen atom. Pseudoephedrine reacts as a weak base, capable of forming salts with various acids, and this property is widely used in pharmaceutical.
Synthesis of Pseudoephedrine
Pseudoephedrine (CAS № 90-82-4) can be obtained by different methods, for example extraction from Ephedra plant, synthesis from ephedrone, 1-phenyl-1,2-propandion or L -phenylacetylcarbinol. Solvent extraction method for obtain pseudoephedrine from Ephedra plant used not often. This chapter describes the chemical reactions to produce pseudoephedrine.
One of the methods for obtaining pseudoephedrine (CAS № 90-82-4) in laboratory is preparation ephedrine from ephedrone with sodium borohydride. In the benzene solution of ephedrone, with intensive stirring in small portions with sodium borohydride. The color of the mixture remains unchanged for a long time, at the end it becomes lighter, orange shades disappear.

Another of the method for obtaining pseudoephedrine is preparation pseudoephedrine from 1-phenyl-1,2-propandion. A mixture of absolute alcohol, 1-phenyl-1,2-propandion and an alcoholic solution of methylamine reduced catalytically with hydrogen in the presence of platinum.

There is a method to get pseudoephedrine from 2-(methylimino)-1-phenyl-1-propanol. This imine usually obtained from L-phenylacetylcarbinol. The 2-(methylimine)-1-phenyl-1-propanol in ethanol reacts with solution of sodium borohydride. For chemical reactions uses microwave irradiation.


Chemical Reactions of Pseudoephedrine
Pseudoephedrine, a phenethylamine derivative, is a compound in pharmaceutical. Its chemical structure allows it to undergo a variety of reactions. This chapter explores chemical reactions of pseudoephedrine.
Reduction of pseudoephedrine is one of the fundamental reactions of pseudoephedrine, primarily due to its implications in illicit drug synthesis, to methamphetamine, a powerful central nervous system stimulant. Pseudoephedrine hydrochloride mixed with red phosphorous, iodine and distilled water. The mixture refluxed and filtered out.

Another way to obtain methamphetamine. Pseudoephedrine hydrochloride mixed with iodine and hypophosphorous acid. The mixture refluxed, then diluted with an equal volume of water.

Pseudoephedrine can also engage in reductive amination processes. For example, using a reducing agent such as melt sodium or lithium with ammonium, after it methamphetamine can be formed.

Oxidation Reactions
Another reaction involving pseudoephedrine is its oxidation. Depending on the conditions and the oxidizing agent used, pseudoephedrine can be oxidized to produce corresponding ketone. For example, the controlled oxidation of pseudoephedrine with chromium(VI) oxide in sulfuric acid can form the corresponding ketone, ephedrone.


Applications of Pseudoephedrine
Pseudoephedrine, due to its pharmacological properties and chemical reactivity, finds applications in pharmacy and synthetic chemistry.
Medicinal Uses
The most recognized application of pseudoephedrine is in the treatment of nasal congestion and sinus pressure associated with colds, allergies, and sinusitis. Acting as a sympathomimetic agent, it stimulates the receptors, leading to vasoconstriction of the blood vessels in the nasal passages, thereby reducing swelling and congestion.
Synthetic Applications
In synthetic chemistry, pseudoephedrine (CAS № 90-82-4) used as a precursor for various organic reactions. For example, synthesis of complex alkaloids and pharmaceuticals, where its chiral center influences the stereochemistry of the resulting molecules.
Precursor in Drug Manufacture
One of the controversial applications of pseudoephedrine (CAS № 90-82-4) is its role as a precursor in the synthesis of methamphetamine, a powerful and addictive stimulant.
The applications of pseudoephedrine extend from its primary use in relieving nasal congestion to playing a crucial role in the synthesis of complex organic molecules. Its medicinal benefits combined with its significance in synthetic chemistry.

Health Effects of Pseudoephedrine
The influence of pseudoephedrine (CAS № 90-82-4) is being studied in pharmaceutical and chemical research and its effects on human health. This chapter discusses the potential health risks associated with working with pseudoephedrine.
Exposure to pseudoephedrine (CAS № 90-82-4), especially in environments where it is synthesized, processed, or used in research, can lead to a number of health problems.
Inhalation of pseudoephedrine powder is the most common route of occupational exposure, potentially causing airway irritation, bronchospasm, or exacerbation of pre-existing asthmatic conditions.
Also, skin exposure may result in skin irritation, rash or allergic dermatitis, especially in people with sensitive skin or pre-existing skin conditions.
Additionally, accidental ingestion, although less common, may result in systemic effects like those observed with therapeutic use, including palpitations, hypertension, dizziness, and insomnia, depending on the amount ingested.

Safety Precautions
When handling pseudoephedrine (CAS № 90-82-4), you should take precautions to protect yourself from the potential health risks associated with its handling. Pseudoephedrine, although therapeutically useful, poses a risk of exposure through inhalation, skin contact, or ingestion in a laboratory setting. The following precautions are designed to minimize these risks and provide a safe working environment.
Personal protective equipment (PPE):
- Gloves: Wear appropriate chemical-resistant gloves to prevent skin contact with pseudoephedrine. Nitrile gloves are often recommended for this work.
- Eye protection: Wear safety goggles or a face shield to protect against splashes and dust.
- Respiratory Protection: In situations where aerosols may be generated, use a respirator or work under a fume hood to avoid inhaling particles.
- Lab Coat: A lab coat should be worn to protect personal clothing and skin.
Conclusion
This article discusses the properties, reactions and uses of pseudoephedrine (CAS № 90-82-4), its chemical reactions and the breadth of its importance in both pharmaceuticals and chemical synthesis. The decongestant properties and chemical interactions of pseudoephedrine illustrate the balance between therapeutic utility and chemical reactivity, highlighting the challenges and opportunities associated with its use and study.
Synthesis and chemical reactions of pseudoephedrine (CAS № 90-82-4) as a precursor in various pharmaceutical products, and approaches to overcome regulatory problems associated with its production and use.
Moreover, research and health studies of pseudoephedrine (CAS № 90-82-4), especially in laboratory settings, highlight the need for safety development to reduce exposure risks.
Bibliography
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- Methamphetamine from ephedrine tablets https://bbgate.com/threads/methamphetamine-from-ephedrine-tablets.302/
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