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How Are Ketones Formed Chemistry

Synthesis Of Aldehydes & Ketones

Synthesis Of Aldehydes & Ketones

Aldehydes and ketones can be prepared using a wide variety of reactions. Although these reactions are discussed in greater detail in other sections, they are listed here as a summary and to help with planning multistep synthetic pathways. Please use the appropriate links to see more details about the reactions. Continue reading >>

Hydrolysis Of Imines To Give Ketones (or Aldehydes)

Hydrolysis Of Imines To Give Ketones (or Aldehydes)

Description: Treatment of imines with water leads to their hydrolysis back to aldehydes (or ketones) and an amine. Notes: The reaction is assisted through the use of an acid catalyst. Examples: Notes: Note that the third example is intramolecular. Mechanism: Protonation of the imine nitrogen (Step 1, arrows A and B) results in the formation of the iminium ion, which undergoes 1,2-addition by water (Step 2, arrows C and D). Transfer of a proton (Step 3, arrows E and F) followed by 1,2 elimination of ammonia (Step 4, arrows G and H) lead to an oxonium ion, which is then deprotonated to give the neutral ketone. Notes: Acid is helpful but not an absolute requirement for this reaction. Reasonable mechanisms can be drawn without acid. The “Cl” here in H3O+ Cl- is completely unimportant, just meant to show a balance of charge for H3O+. Other counter ions such as Br-, HSO3-, etc. would work just as well. Note that this is an equilibrium reaction and goes in this direction because of the large excess of water. It is the exact reverse of imine formation. There are certainly other reasonable ways to draw proton transfer (Step 3) and other species besides H2O that could conceivably act as bases in the last step. Organic Chemistry 2 builds on the concepts from Org 1 and introduces a lot of new reactions. Here is an index of posts for relevant topics in Organic Chemistry 2: [Hint – searching for something specific? Try CNTRL-F] General Posts About Organic Chemistry 2 Oxidation And Reduction Alcohols, Ethers, And Epoxides Conjugation, Dienes and Pericyclic Reactions Aromaticity and Aromatic Reactions Aldehydes and Ketones Carboxylic Acid Derivatives General Posts Concerning Organic Chemistry 2 Oxidation And Reduction Alcohols, Epoxides, And Ethers Alcohols (1) Nomenclature And P Continue reading >>

Production And Metabolism Of Non-esterified Fatty Acids

Production And Metabolism Of Non-esterified Fatty Acids

Lipolysis of fat stored as triglycerides in adipose tissue occurs in response to increasing energy demands that cannot be adequately supplied by glucose. Hormones, such as glucagon, catecholamines, ACTH, corticosteroids and growth hormone, stimulate hormone-sensitive lipase, whereas insulin inhibits this enzyme. Lipolysis of triglycerides releases NEFAs (which are usually long-chain fatty acids) and glycerol. Glycerol is taken up by cells and used for glucose production or can be used to re-form triglycerides. NEFAs are water-insoluble and are transported bound to albumin. Once taken up by hepatocytes, NEFAs are esterified. The esterified fatty acids then have several fates: 1) They can recombine with glycerol to form triglycerides, which are packaged into VLDL. The VLDL are exported from the liver or (if produced in excess) are stored as fat within the hepatocyte (eventually causing lipidosis). 2) They can enter the mitochondria (in a reaction that requires carnitine) and be used for energy production (through the Kreb’s cycle) or ketone formation. Within the mitochondria, esterified fatty acids undergo β-oxidation to acetyl CoA. Acetyl CoA combines with oxaloacetate in the Kreb’s cycle (tricarboxylic acid cycle) to form citrate. Continued oxidation in this cycle leads to energy (ATP) production. If oxaloacetate supplies are low (oxaloacetate is used as a substrate for gluconeogenesis in states of negative energy balance), acetyl CoA is then used to form ketones. Continue reading >>

Ketosis, Ketones, And How It All Works

Ketosis, Ketones, And How It All Works

Ketosis is a process that the body does on an everyday basis, regardless of the number of carbs you eat. Your body adapts to what is put in it, processing different types of nutrients into the fuels that it needs. Proteins, fats, and carbs can all be processed for use. Eating a low carb, high fat diet just ramps up this process, which is a normal and safe chemical reaction. When you eat carbohydrate based foods or excess amounts of protein, your body will break this down into sugar – known as glucose. Why? Glucose is needed in the creation of ATP (an energy molecule), which is a fuel that is needed for the daily activities and maintenance inside our bodies. If you’ve ever used our keto calculator to determine your caloric needs, you will see that your body uses up quite a lot of calories. It’s true, our bodies use up much of the nutrients we intake just to maintain itself on a daily basis. If you eat enough food, there will likely be an excess of glucose that your body doesn’t need. There are two main things that happen to excess glucose if your body doesn’t need it: Glycogenesis. Excess glucose will be converted to glycogen and stored in your liver and muscles. Estimates show that only about half of your daily energy can be stored as glycogen. Lipogenesis. If there’s already enough glycogen in your muscles and liver, any extra glucose will be converted into fats and stored. So, what happens to you once your body has no more glucose or glycogen? Ketosis happens. When your body has no access to food, like when you are sleeping or when you are on a ketogenic diet, the body will burn fat and create molecules called ketones. We can thank our body’s ability to switch metabolic pathways for that. These ketones are created when the body breaks down fats, creating Continue reading >>

Organic Chemistry/ketones And Aldehydes

Organic Chemistry/ketones And Aldehydes

Aldehydes () and ketones () are both carbonyl compounds. They are organic compounds in which the carbonyl carbon is connected to C or H atoms on either side. An aldehyde has one or both vacancies of the carbonyl carbon satisfied by a H atom, while a ketone has both its vacancies satisfied by carbon. 3 Preparing Aldehydes and Ketones Ketones are named by replacing the -e in the alkane name with -one. The carbon chain is numbered so that the ketone carbon, called the carbonyl group, gets the lowest number. For example, would be named 2-butanone because the root structure is butane and the ketone group is on the number two carbon. Alternatively, functional class nomenclature of ketones is also recognized by IUPAC, which is done by naming the substituents attached to the carbonyl group in alphabetical order, ending with the word ketone. The above example of 2-butanone can also be named ethyl methyl ketone using this method. If two ketone groups are on the same structure, the ending -dione would be added to the alkane name, such as heptane-2,5-dione. Aldehydes replace the -e ending of an alkane with -al for an aldehyde. Since an aldehyde is always at the carbon that is numbered one, a number designation is not needed. For example, the aldehyde of pentane would simply be pentanal. The -CH=O group of aldehydes is known as a formyl group. When a formyl group is attached to a ring, the ring name is followed by the suffix "carbaldehyde". For example, a hexane ring with a formyl group is named cyclohexanecarbaldehyde. Aldehyde and ketone polarity is characterized by the high dipole moments of their carbonyl group, which makes them rather polar molecules. They are more polar than alkenes and ethers, though because they lack hydrogen, they cannot participate in hydrogen bonding like Continue reading >>

Synthesis Of Ketones

Synthesis Of Ketones

Like aldehydes, ketones can be prepared in a number of ways. The following sections detail some of the more common preparation methods: the oxidation of secondary alcohols, the hydration of alkynes, the ozonolysis of alkenes, Friedel‐Crafts acylation, the use of lithium dialkylcuprates, and the use of a Grignard reagent. The oxidation of secondary alcohols to ketones may be carried out using strong oxidizing agents, because further oxidation of a ketone occurs with great difficulty. Normal oxidizing agents include potassium dichromate (K 2Cr 2O 7) and chromic acid (H 2CrO 4). The conversion of 2‐propanol to 2‐propanone illustrates the oxidation of a secondary alcohol. The addition of water to an alkyne leads to the formation of an unstable vinyl alcohol. These unstable materials undergo keto‐enol tautomerization to form ketones. The hydration of propyne forms 2‐propanone, as the following figure illustrates. When one or both alkene carbons contain two alkyl groups, ozonolysis generates one or two ketones. The ozonolysis of 1,2‐dimethyl propene produces both 2‐propanone (a ketone) and ethanal (an aldehyde). Friedel‐Crafts acylations are used to prepare aromatic ketones. The preparation of acetophenone from benzene and acetyl chloride is a typical Friedel‐Crafts acylation. The addition of a lithium dialkylcuprate (Gilman reagent) to an acyl chloride at low temperatures produces a ketone. This method produces a good yield of acetophenone. Hydrolysis of the salt formed by reacting a Grignard reagent with a nitrile produces good ketone yields. For example, you can prepare acetone by reacting the Grignard reagent methyl magnesium bromide (CH 3MgBr) with methyl nitrile (CH 3C&tbond;N). Continue reading >>

Ketone

Ketone

Ketone, any of a class of organic compounds characterized by the presence of a carbonyl group in which the carbon atom is covalently bonded to an oxygen atom. The remaining two bonds are to other carbon atoms or hydrocarbon radicals (R): Ketone compounds have important physiological properties. They are found in several sugars and in compounds for medicinal use, including natural and synthetic steroid hormones. Molecules of the anti-inflammatory agent cortisone contain three ketone groups. Only a small number of ketones are manufactured on a large scale in industry. They can be synthesized by a wide variety of methods, and because of their ease of preparation, relative stability, and high reactivity, they are nearly ideal chemical intermediates. Many complex organic compounds are synthesized using ketones as building blocks. They are most widely used as solvents, especially in industries manufacturing explosives, lacquers, paints, and textiles. Ketones are also used in tanning, as preservatives, and in hydraulic fluids. The most important ketone is acetone (CH3COCH3), a liquid with a sweetish odour. Acetone is one of the few organic compounds that is infinitely soluble in water (i.e., soluble in all proportions); it also dissolves many organic compounds. For this reason—and because of its low boiling point (56 °C [132.8 °F]), which makes it easy to remove by evaporation when no longer wanted—it is one of the most important industrial solvents, being used in such products as paints, varnishes, resins, coatings, and nail-polish removers. The International Union of Pure and Applied Chemistry (IUPAC) name of a ketone is derived by selecting as the parent the longest chain of carbon atoms that contains the carbonyl group. The parent chain is numbered from the end that Continue reading >>

Reactions Of Alcohols To Give Acetals

Reactions Of Alcohols To Give Acetals

Reactions of Alcohols to give Acetals Reaction type: Nucleophilic Addition then nucleophilic substitution Summary Typical reagents : excess ROH, catalytic p-toluenesulfonic acid (often written as TsOH) in refluxing benzene. Aldehydes and ketones react with two moles of an alcohol to give 1,1-geminal diethers more commonly known as acetals. The term "acetal" used to be restricted to systems derived from aldehydes and the term "ketal" applied to those from ketones, but chemists now use acetal to describe both. Acetals are biologically important due to their role in the chemistry of carbohydrates. Acetals are important chemically due to their role as "protecting groups" The equilibrium is shifted towards the acetal by using an excess of the alcohol and/or removing water as it forms. It is also possible to use 1,2- or 1,3-diols to form cyclic acetals, two common examples are shown below: Acetals can be readily converted back to the aldehyde or ketone by heating with aqueous acid. The mechanism for this is the reverse of that shown below for acetal formation. Study Tip: The important "piece" of an acetal is the central C which becomes the C of the carbonyl C=O. It can be recognised by looking for the C that is attached to two O atoms by single bonds. Related Reactions Reaction type: Oxidation - reduction Summary Aldehydes, RCHO, can be oxidised to carboxylic acids, RCO2H. Ketones are not oxidised under these conditions as they lack the critical H for the elimination to occur (see mechanism below). The reactive species in the oxidation is the hydrate formed when the aldehyde reacts with the water. Typical reagents are aqueous Cr (VI) species: Related Reactions Oxidation of Alcohols The Baeyer-Villager Reaction Reaction type: Oxidation-reduction via Nucleophilic addition Summa Continue reading >>

Aldehydes And Ketones Formation: Copper-catalyzed Aerobic Oxidative Decarboxylation Of Phenylacetic Acids And Α-hydroxyphenylacetic Acids

Aldehydes And Ketones Formation: Copper-catalyzed Aerobic Oxidative Decarboxylation Of Phenylacetic Acids And Α-hydroxyphenylacetic Acids

Abstract Aromatic aldehydes or ketones from copper catalyzed aerobic oxidative decarboxylation of phenylacetic acids and α-hydroxyphenylacetic acids have been synthesized. This reaction combined decarboxylation, dioxygen activation, and C–H bond oxidation steps in a one-pot protocol with molecular oxygen as the sole terminal oxidant. This reaction represents a novel decarboxylation of an sp3-hybridized carbon and the use of a benzylic carboxylic acid as a source of carbonyl compounds. Citation data is made available by participants in Crossref's Cited-by Linking service. For a more comprehensive list of citations to this article, users are encouraged to perform a search inSciFinder. Continue reading >>

The Simple Two-step Pattern For Seven Key Reactions Of Aldehydes And Ketones

The Simple Two-step Pattern For Seven Key Reactions Of Aldehydes And Ketones

“There are just so many reactions! I can’t remember all the mechanisms!!” – distressed organic chemistry student Yes, yes there are a lot of reactions, particularly in second semester organic chemistry. But there is good news on this front: there is a tremendous amount of repetition in these reactions. For instance, what if I told you that there was a simple, two-step pattern behind seven different reactions that each work for aldehydes and ketones? By learning this key pattern, you’d therefore know the mechanism for 7*2 = 14 different reactions. That would be useful, right? The two steps are the following: Addition of a nucleophile to an aldehyde or ketone Protonation of the negatively charged oxygen with acid (often called “acidic workup”) That’s it. Here’s the general case for the reaction. I’ve drawn an aldehyde here, but everything I will say here also applies to ketones. What bonds form, and what bonds break? Hopefully you can see that a C–O (π) bond is being broken, a C–Nu bond is being formed, and an O–H bond is formed also. Any mechanism we draw has to account for these bond-forming and bond-breaking events. Step 1 is addition of a nucleophile to the electrophilic carbonyl carbon. This forms C–Nu and breaks C–O (π), resulting in a negatively charged oxygen. Step 2 is addition of an acid (“protonation”), which results in formation of the O–H bond. This is generally done after the reaction with the nucleophile is complete – otherwise the acid would destroy the nucleophile, sometimes in violent fashion (e.g. LiAlH4 is not something you’d want to bring in close proximity to acid). Here’s the general mechanism: This two-step pattern is behind the following seven reactions: Again, although aldehydes are pictured here, the r Continue reading >>

What Is Ketone? - Definition, Structure, Formation & Formula

What Is Ketone? - Definition, Structure, Formation & Formula

Background of Ketone Did you know that our friend aldehyde has a very close relative named ketone? By definition, a ketone is an organic compound that contains a carbonyl functional group. So you may be wondering if aldehydes and ketones are relatives, what makes them different? Well, I am glad you asked because all you have to remember is this little guy: hydrogen. While aldehyde contains a hydrogen atom connected to its carbonyl group, ketone does not have a hydrogen atom attached. There are a few ways to know you are encountering a ketone. The first is by looking at the ending of the chemical word. If the suffix ending of the chemical name is '-one,' then you can be sure there is a ketone present in that compound. Want to know another way to tell if a ketone is lurking around the corner? By its physical property. Ketones have high boiling points and love water (high water solubility). Let's dig a little deeper with the physical property of a ketone. The oxygen in a ketone absolutely loves to take all the electrons it can get its hands on. But, by being an electron-hogger, oxygen's refusal to share creates a sticky situation where some atoms on the ketone have more or less charge than others. In chemistry, an electron-hogging atom is referred to as being electronegative. An electronegative atom is more attractive to other compounds. This attractiveness, called polarity, is what contributes to ketones' physical properties. Structure & Formula Ketones have a very distinct look to them; you can't miss it if you see them. As shown in Diagram 1, there are two R groups attached to the carbonyl group (C=O). Those R groups can be any type of compound that contains a carbon molecule. An example of how the R group determines ketone type is illustrated in this diagram here. The Continue reading >>

Formation Of Hydrates

Formation Of Hydrates

Voiceover: Here's an example of a nucleophilic addition reaction to an aldehyde or a ketone. So over here on the left, it could be an aldehyde, or we could change that to form a ketone. And if you add water to an aldehyde or ketone, you form this product over here on the right, which is called a hydrate, or also called a gem-diol, or geminal diol because these two OHs here are on the same carbon, so like they're twins. And this reaction is at equilibrium. So let's think about the aldehyde, or the ketone. We know the carbonyl on the aldehyde or ketone is polarized, so we know that the oxygen has more electronegatives than carbons, so it withdraws some electron densities. So this oxygen here is partially negative, and this carbonyl carbon is partially positive, like that. And therefore the carbonyl carbon, since it's partially positive, is electrophillic, so it wants electrons. And it can get electrons from water. So let's go ahead and draw the water molecule right here. Water can function as a nucleophile. It has two lone pairs of electrons, this oxygen here is partially negative, and so we're going to get a nucleophile attacking our electrophile. So a lone pair of electrons on the oxygen is going to attack our carbonyl carbon like that, So the nucleophile attacks the electrophillic portion of the molecule, and these pi electrons here kick off onto the oxygen. So let's go ahead and draw the results of our nucleophilic attack here, and so we now have our oxygen bonded to this carbon, and this oxygen still has two hydrogens bonded to it, so I'm gonna go ahead and draw in those two hydrogens. There's still a lone pair of electrons on that oxygen, which gives that oxygen a +1 formal charge. And then this carbon here is bonded to another oxygen, which had two lone pairs of el Continue reading >>

Making Aldehydes And Ketones

Making Aldehydes And Ketones

This page explains how aldehydes and ketones are made in the lab by the oxidation of primary and secondary alcohols. Oxidising alcohols to make aldehydes and ketones General The oxidising agent used in these reactions is normally a solution of sodium or potassium dichromate(VI) acidified with dilute sulphuric acid. If oxidation occurs, the orange solution containing the dichromate(VI) ions is reduced to a green solution containing chromium(III) ions. The net effect is that an oxygen atom from the oxidising agent removes a hydrogen from the -OH group of the alcohol and one from the carbon to which it is attached. R and R' are alkyl groups or hydrogen. They could also be groups containing a benzene ring, but I'm ignoring these to keep things simple. If at least one of these groups is a hydrogen atom, then you will get an aldehyde. If they are both alkyl groups then you get a ketone. If you now think about where they are coming from, you will get an aldehyde if your starting molecule looks like this: In other words, if you start from a primary alcohol, you will get an aldehyde. You will get a ketone if your starting molecule looks like this: . . . where R and R' are both alkyl groups. Secondary alcohols oxidise to give ketones. Making aldehydes Aldehydes are made by oxidising primary alcohols. There is, however, a problem. The aldehyde produced can be oxidised further to a carboxylic acid by the acidified potassium dichromate(VI) solution used as the oxidising agent. In order to stop at the aldehyde, you have to prevent this from happening. Note: This further oxidation is explained in more detail on the page about oxidation of alcohols. If you choose to follow this link (not important for the purposes of the present page), use the BACK button on your browser to return to t Continue reading >>

Formation Of Hydrates From Aldehydes/ketones And H2o

Formation Of Hydrates From Aldehydes/ketones And H2o

Hi Carrie, the difference is one extra step. Under basic conditions, HO- would attack the carbonyl carbon in an “addition” step. Then in the second step, the resulting O- would be protonated by water to give OH [2 steps] Under acidic conditions, you’d protonate the carbonyl oxygen, which makes it a better electrophile. Then, water would attack the carbonyl carbon. Then, there’s be a deprotonation of the oxygen that just attacked (since now it’s R-OH2 + ) by a molecule of solvent (H2O) to give the neutral hydrate. [3 steps] Organic Chemistry 2 builds on the concepts from Org 1 and introduces a lot of new reactions. Here is an index of posts for relevant topics in Organic Chemistry 2: [Hint – searching for something specific? Try CNTRL-F] General Posts About Organic Chemistry 2 Oxidation And Reduction Alcohols, Ethers, And Epoxides Conjugation, Dienes and Pericyclic Reactions Aromaticity and Aromatic Reactions Aldehydes and Ketones Carboxylic Acid Derivatives General Posts Concerning Organic Chemistry 2 Oxidation And Reduction Alcohols, Epoxides, And Ethers Alcohols (1) Nomenclature And Properties How To Make Alcohols More Reactive Alcohols (3) Acidity And Basicity The Williamson Ether Synthesis Williamson Ether Synthesis: Planning Synthesis of Ethers (2) – Back To The Future! Ether Synthesis Via Alcohol And Acid Cleavage Of Ethers With Acid Epoxides – The Outlier Of The Ether Family Opening Of Epoxides With Acid Opening Of Epoxides With Base Making Alkyl Halides From Alcohols Tosylates And Mesylates PBr3 And SOCl2 Elimination Reactions Of Alcohols Elimination Of Alcohols To Alkenes With POCl3 Alcohol Oxidation: “Strong” And “Weak” Oxidants Demystifying Alcohol Oxidations Intramolecular Reactions Of Alcohols And Ethers Protecting Groups For Alcohol Continue reading >>

Formation Of Imines From Primary Amines And Ketones

Formation Of Imines From Primary Amines And Ketones

Description: Reaction of a primary amine with an aldehyde or ketone results in an imine. The reaction results in the formation of one equivalent of water. Content available for Reactionguide members only. Not a member? Get access for about 30 cents / day! For the first step, why does e proton source attack the carbonyl oxygen instead of the more basic amine in the reaction mixture? Is it because of resonance in e protonated carbonyl? Do we add e acid and e amine at the same time? Can the acid be a weak acid as strong acidic conditions may protonate e amine and render it non nucleophilic? Thanks :) The amine is more basic, this is true! Acid can attack the amine, but it doesn’t go anywhere (the amine and protonated amine are in equilibrium). It’s a dead end, in other words. You just need a little bit of protonated carbonyl to get the reaction going. It’s important that the solution not be too acidic, since if all the amine is protonated (irreversibly) then there is no nucleophile that would be able to attack the carbonyl. Website Organic Chemistry 2 builds on the concepts from Org 1 and introduces a lot of new reactions. Here is an index of posts for relevant topics in Organic Chemistry 2: [Hint – searching for something specific? Try CNTRL-F] General Posts About Organic Chemistry 2 Oxidation And Reduction Alcohols, Ethers, And Epoxides Conjugation, Dienes and Pericyclic Reactions Aromaticity and Aromatic Reactions Aldehydes and Ketones Carboxylic Acid Derivatives General Posts Concerning Organic Chemistry 2 Oxidation And Reduction Alcohols, Epoxides, And Ethers Alcohols (1) Nomenclature And Properties How To Make Alcohols More Reactive Alcohols (3) Acidity And Basicity The Williamson Ether Synthesis Williamson Ether Synthesis: Planning Synthesis of Ethers (2) Continue reading >>

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