chemistry

Pempidine

Pempidine is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pempidine rather than just read about it. In short: Pempidine is a nicotinic antagonist drug, first reported in 1958 by two research groups working independently, and introduced as an oral treatment for hypertension. Pharmacology Reports on the "classical" pharmacology of pempidine have been published.

Key takeaways

Pempidine belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pempidine to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pempidine from memory before moving on to harder problems.

Reference excerpt

Pempidine is a nicotinic antagonist drug, first reported in 1958 by two research groups working independently, and introduced as an oral treatment for hypertension.

Pharmacology Reports on the "classical" pharmacology of pempidine have been published. The Spinks group, at ICI, compared pempidine, its N-ethyl analogue, and mecamylamine in considerable detail, with additional data related to several structurally simpler compounds.

Toxicology LD50 for the HCl salt of pempidine in mice: 74 mg/kg (intravenous); 125 mg/kg (intraperitoneal); 413 mg/kg (oral).

Chemistry Pempidine is an aliphatic, sterically hindered, cyclic, tertiary amine, which is a weak base: in its protonated form it has a pKa of 11.25. Pempidine is a liquid with a boiling point of 187–188 °C and a density of 0.858 g/cm3. Two early syntheses of this compound are those of Leonard and Hauck, and Hall. These are very similar in principle: Leonard and Hauck reacted phorone with ammonia, to produce 2,2,6,6-tetramethyl-4-piperidone, which was then reduced by means of the Wolff–Kishner reduction to 2,2,6,6-tetramethylpiperidine. This secondary amine was then N-methylated using methyl iodide and potassium carbonate. Hall's method involved reacting acetone with ammonia in the presence of calcium chloride to give 2,2,6,6-tetramethyl-4-piperidone, which was then reduced under Wolff–Kishner conditions, followed by N-methylation of the resulting 2,2,6,6-tetramethylpiperidine with methyl p-toluenesulfonate.

References

External links Pempidine at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

Illustrations

Worked examples

Example 1 — a first encounter with Pempidine

Start with the simplest possible case. Write down what Pempidine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pempidine before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pempidine ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pempidine

In research: Pempidine appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pempidine in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pempidine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Nicotinic antagonists, Piperidines, Reagents for organic chemistry, so understanding it makes those chapters shorter.
In everyday life: Look for Pempidine outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pempidine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pempidine means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pempidine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pempidine in simple terms?

Pempidine is a nicotinic antagonist drug, first reported in 1958 by two research groups working independently, and introduced as an oral treatment for hypertension. Pharmacology Reports on the "classical" pharmacology of pempidine have been published.

Why does Pempidine matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pempidine?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pempidine.