chemistry

Novaluron

Novaluron 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 Novaluron rather than just read about it. In short: Novaluron, or (±)-1-[3-chloro-4-(1,1,2-trifluoro-2-trifluoro- methoxyethoxy)phenyl]-3-(2,6-difluorobenzoyl)urea, is a chemical with pesticide properties, belonging to the class of insecticides called insect growth regulators. It is a benzoylphenyl urea developed by Makhteshim-Agan Industries Ltd..

Key takeaways

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

Reference excerpt

Novaluron, or (±)-1-[3-chloro-4-(1,1,2-trifluoro-2-trifluoro- methoxyethoxy)phenyl]-3-(2,6-difluorobenzoyl)urea, is a chemical with pesticide properties, belonging to the class of insecticides called insect growth regulators. It is a benzoylphenyl urea developed by Makhteshim-Agan Industries Ltd.. In the United States, the compound has been used on food crops, including apples, potatoes, brassicas, ornamentals, and cotton. Patents and registrations have been approved or are ongoing in several other countries throughout Europe, Asia, Africa, South America, and Australia. The US Environmental Protection Agency and the Canadian Pest Management Regulatory Agency consider novaluron to pose low risk to the environment and non-target organisms and value it as an important option for integrated pest management that should decrease reliance on organophosphorus, carbamate and pyrethroid insecticides.

History

Legislation In the European Union, a registration application was filed in 2001, but in 2007 there was still no definitive agreement regarding the legal status of novaluron. Member states of the European Union were allowed to award temporary permits for products based on novaluron. On April 4, 2012, a decision was disclosed which discontinued permits for the use of novaluron, to be executed on October 3. The development of the legal status of novaluron in Japan is condensed in the timeline below.

Timeline of approval in Japan

Synthesis Novaluron can be synthesized in a four-step reaction process. First, 2-chloro-4-nitrophenol is converted into chloro-4-aminophenol through a reduction reaction. After this first step, an addition reaction with perfluoro-vinyl-perfluoro-methyl ether is conducted to synthesize 3-chloro-4-[1,1,2-trifluoro2-(trifluoromethoxy)-ethoxy]aniline. The next step in the process is the production of 2,6-difluorobenzoyl isocyanate in an acylation reaction using 2,6-difluorobenzamide and oxalyl dichloride. The final part of the synthesis of novaluron is an addition reaction with 3-chloro-4-[1,1,2-trifluoro-2-(trifluoromethoxy)-ethoxy]aniline.

Reactivity and mechanism of action The exact mechanism of action of novaluron has not been extensively researched, but the general mechanisms and effects common to benzoylphenyl ureas apply. The compound inhibits chitin formation, targeting specifically larval insect stages that actively synthesize chitin. The adults of non-target species are seldom affected. Benzoylphenyl ureas, including novaluron, do not inhibit chitin synthesis in cell free systems or block the chitin biosynthetic pathway in intact larvae. The precise biochemical activity of these compounds, that gives them their insecticidal activity, has not yet been elucidated. The most likely hypothesis is that benzoylphenyl ureas interrupt the in vivo synthesis and transport of specific proteins required for assemblage of polymeric chitin.

Metabolism After oral administration in rats, novaluron treated with chlorophenyl-14C, only about 6-7% of the administered dose was absorbed after a single low dose (2 mg per kilogram bodyweight). A single high dose (1000 mg per kilogram bodyweight) caused an absorption that was 10-fold less. In another experiment [difluorophenyl-14C(U)]novaluron caused an absorption of approximately 20%, but this number may be an overestimate due to cleavage of novaluron in the gastrointestinal tract. Through whole-body autoradiography it was demonstrated that the concentrations of radioactivity were highest in the kidneys, liver, fat tissues, pancreas and in the mesenteric lymph nodes, while the lowest concentrations appeared to be in the thymus, eyes, brain, testes, bone, muscles, and blood.

Biotransformation In a study of absorption, distribution, metabolism (biotransformation) and excretion of novaluron, rats received radioactively labeled novaluron orally. The absorbed novaluron was metabolized and 14 and 15 components were detected in the urine and bile respectively. The main metabolic pathway was cleavage of the urea bridge between the chlorophenyl- and difluorophenylgroups. The products of this reaction are 2,6-difluorobenzoic acid and 3-chloro-4-(1,1,2-trifluoro-2-trifluoromethoxyethoxy) aniline. Most of the radioactivity consisted of unchanged novaluron. The parent compound was also the major component present in extracts from fat, liver and kidneys. The proposed metabolic pathway is shown in the adjacent image.

Efficacy Benzoylphenyl ureas have provided consistently good results when applied properly against certain susceptible pests. Novaluron in particular has been shown to have insecticidal activity against several important pests. Bioactivity of novaluron is usually much greater than that of insecticides diflubenzuron and teflubenzuron and the compound is at least as active as other insecticides from its developmental generation, for example chlorofluazuron and lufenuron. In comparison to other benzoylphenyl ureas, novaluron demonstrates improved contact toxicity, while the probable mechanism of action remains the same. Novaluron has been shown to be highly active against a number of common pests, such as the Colorado potato beetle, whiteflies, African cotton leafworm, and cotton bollworm. Organisms that are closely related to these animals seem to share this susceptibility to the compound. A notable exception to this is a study evaluating the efficacy of various insecticides on the stem borers Diatraea saccharalis and Eoreuma loftini, in which the results seemed to indicate that these organisms were not susceptible to novaluron.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Novaluron

Start with the simplest possible case. Write down what Novaluron 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 Novaluron 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 Novaluron 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 Novaluron

In research: Novaluron 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 Novaluron 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: Novaluron is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2,6-Difluorophenyl compounds, Acylureas, Chlorobenzene derivatives, so understanding it makes those chapters shorter.
In everyday life: Look for Novaluron 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 Novaluron in 20 minutes

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

Frequently asked questions

What is Novaluron in simple terms?

Why does Novaluron 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 Novaluron?

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 Novaluron.