mathematics

Thioureas

Thioureas is a mathematics 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 Thioureas rather than just read about it. In short: In organic chemistry, thioureas are members of a family of organosulfur compounds with the formula S=C(NR2)2 and structure R2N−C(=S)−NR2. The parent member of this class of compounds is thiourea (S=C(NH2)2).

Key takeaways

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

Reference excerpt

In organic chemistry, thioureas are members of a family of organosulfur compounds with the formula S=C(NR2)2 and structure R2N−C(=S)−NR2. The parent member of this class of compounds is thiourea (S=C(NH2)2). Substituted thioureas are found in several commercial chemicals.

Structure and bonding Thioureas have a trigonal planar molecular geometry of the N2C=S core. The C=S bond distance is near 1.71 Å, which is 0.1 Å longer than in normal ketones (R2C=O). The C–N bond distances are short. Thioureas occurs in two tautomeric forms.

On the other hand, some compounds depicted as isothioureas and in fact thioureas, one example being mercaptobenzimidazole.

Synthesis N,N′-unsubstituted thioureas can be prepared by treating the corresponding cyanamide with hydrogen sulfide or similar sulfide sources. Organic ammonium salts react with potassium thiocyanate as the source of the thiocarbonyl (C=S). Alternatively, N,N′-disubstituted thioureas can be prepared by coupling two amines with thiophosgene:

HNR2 + S=CCl2 → 2 S=C(NR2)2 + 2 HCl Amines also condense with organic thiocyanates to give thioureas:

HNR2 + S=C=NR' → S=C(NR2)(NHR') Cyclic thioureas are prepared by transamidation of thiourea with diamines. Ethylene thiourea is synthesized by treating ethylenediamine with carbon disulfide. In some cases, thioureas can be prepared by thiation of ureas using phosphorus pentasulfide.

Reactions

Thioureas are susceptible to tautomerization. For the parent thiourea, the thione tautomer predominates in aqueous solutions. The thiol form, known as an isothiourea, can be encountered in substituted compounds such as isothiouronium salts. Thioureas are nucleophilic at sulfur. When they contain a pair of N-H substituents, thioureas engage in hydrogen bonding. This interaction is the basis of a research theme called thiourea organocatalysis. Thioureas are often found to be stronger hydrogen-bond donors (i.e., more acidic) than ureas.

Applications and occurrence Agrichemicals that feature the thiourea functional group include diafenthiuron, methimazole, carbimazole (converted in vivo to methimazole), and propylthiouracil. α-Naphthylthiourea is a commercial rodenticide. Some thioureas are vulcanization accelerators. Ergothioneine, which is derived from histidine, is a rare example of a thiourea found in nature. The cyclic of thiourea called thiamazole is used to treat overactive thyroid

References

Further reading Patai, S., ed. (1977). The Chemistry of double-bonded functional groups. New York, NY: John Wiley & Sons. pp. 1355–1496. ISBN 0-471-92493-8.

External links INCHEM assessment of thiourea International Chemical Safety Card 0680

Illustrations

Worked examples

Example 1 — a first encounter with Thioureas

Start with the simplest possible case. Write down what Thioureas claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, 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 Thioureas 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 Thioureas 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 Thioureas

In research: Thioureas appears in mathematics 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 Thioureas 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: Thioureas is common in secondary-school and first-year university syllabi. It links to neighbouring topics Functional groups, Thioureas, so understanding it makes those chapters shorter.
In everyday life: Look for Thioureas 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 Thioureas in 20 minutes

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

Frequently asked questions

What is Thioureas in simple terms?

Why does Thioureas matter?

Because it connects several mathematics 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 Thioureas?

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 Thioureas.