chemistry

N-Nitrosamides

N-Nitrosamides 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 N-Nitrosamides rather than just read about it. In short: Nitrosamides are chemical compounds that contain the chemical structure R1C(=X)N(–R2)–N=O, that is, a nitroso group bonded to the nitrogen of an amide or similar functional group. Specific classes include the N-nitrosamides, N-nitrosoureas, N-nitrosoguanidines, and N-nitrosocarbamates.

Key takeaways

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

Reference excerpt

Nitrosamides are chemical compounds that contain the chemical structure R1C(=X)N(–R2)–N=O, that is, a nitroso group bonded to the nitrogen of an amide or similar functional group. Specific classes include the N-nitrosamides, N-nitrosoureas, N-nitrosoguanidines, and N-nitrosocarbamates. Nitrosamides are usually chemically reactive, metabolically unstable, and often carcinogenic; however, in contrast to the N-nitrosamines, N-nitrosamides are not generally contaminants found in food.

Use Various chloroethylnitrosoureas (such as N, N'-bis (2-chloroethyl)nitrosourea, BCNU) have obtained a medical use in the field of malignant tumors. It is hypothesized that the efficacy against cancer cells is based on the alkylability of guanine cytosine centers in the sequences of the genetic material, especially the oncogenes.

Synthesis N-Nitrosamides can be prepared starting from N-monosubstituted carboxamides and the nitrosyl cation (which results from the nitrous cation in the presence of strong acids from the nitrous acid), here exemplified for N-methylacetamide (1). The carboxamide reacts in a nucleophilic attack at the nitrosyl cation. After the elimination of a proton, an N-nitrosamide (2) is formed from the resulting cation:

Toxicity The genotoxic effect of the N-nitroso compounds can be attributed to the formation of reactive electrophilic species in the metabolism. The spontaneous decomposition of N-nitroso-ureas in the aqueous medium of the metabolism, here for example of 1-methylnitrosourea (3), produces diazonium or carbenium ions, respectively. The decomposition occurs into isocyanic acid and methyldiazohydroxide. The rearrangement to the diazonium ion and the subsequent elimination of nitrogen results in a carbenium ion (4), which can alkylate nucleophilic intersections of the DNA.

In the organism, the decomposition of N-nitroso ureas with a higher degree of substitution can proceed. An alternative possible formation of diazonium and carbenium ions is through the enzymatic reaction of nitrosamines. Typical accompanying symptoms during the medical cancer treatment via N-nitroso ureas are the impairment of bone marrow (damage of the stem cell compartment), lymphatic tissue and the gastrointestinal tract.

References

External links "nitrosamide". Wiktionary. Retrieved 2017-08-28.

Illustrations

Worked examples

Example 1 — a first encounter with N-Nitrosamides

Start with the simplest possible case. Write down what N-Nitrosamides 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 N-Nitrosamides 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 N-Nitrosamides 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 N-Nitrosamides

In research: N-Nitrosamides 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 N-Nitrosamides 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: N-Nitrosamides is common in secondary-school and first-year university syllabi. It links to neighbouring topics Amides, Nitroso compounds, so understanding it makes those chapters shorter.
In everyday life: Look for N-Nitrosamides 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 N-Nitrosamides in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what N-Nitrosamides 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 N-Nitrosamides out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is N-Nitrosamides in simple terms?

Why does N-Nitrosamides 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 N-Nitrosamides?

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 N-Nitrosamides.