diabetestalk.net

How Are Ketones Acidic

Acid-catalysed Bromination Of Ketones

Acid-catalysed Bromination Of Ketones

Click the structures and reaction arrows in sequence to view the 3D models and animations respectively Bromination of ketones occurs smoothly with bromine in acetic acid. The first step occurs in a cyclic way resulting in protonation of the carbonyl and formation of the enol occuring at the same time. The next step is the attack of the enol on the bromine. The proton on the carbonyl is then lost to yield bromoacetone. M. F. Ruasse, in Advances in Physical Organic Chemistry, 1993, vol. 28, pp. 207–291. 461 1085 Continue reading >>

Acidity Of

Acidity Of

a-Hydrogens In the following table, the acidity of the H for various enolate systems and other closely related systems are given. You should be able to justify the trends in this data ! Why are the protons adjacent to carbonyl groups acidic ? As we have advocated before, look at the stabilisation of the conjugate base. Notice the proximity of the adjacent p system, and hence the possibility for RESONANCE stabilisation by delocalisation of the negative charge to the more electronegative oxygen atom. The more effective the resonance stabilisation of the negative charge, the more stable the conjugate base is and therefore the more acidic the parent system. Let's compare pKa of the common systems: aldehyde pKa = 17, ketone pKa = 19 and an ester pKa = 25, and try to justify the trend. The difference between the 3 systems is in the nature of the group attached to the common carbonyl. The aldehyde has a hydrogen, the ketone an alkyl- group and the ester an alkoxy- group. H atoms are regarded as having no electronic effect : they don't withdraw or donate electrons. Alkyl groups are weakly electron donating, they tend to destabilise anions (you should recall that they stabilise carbocations). This is because they will be "pushing" electrons towards a negative system which is unfavourable electrostatically. Hence, the anion of a ketone, where there are extra alkyl groups is less stable than that of an aldehyde, and so, a ketone is less acidic. In the ester, there is also a resonance donation from the alkoxy group towards the carbonyl that competes with the stabilisation of the enolate charge. This makes the ester enolate less stable than those of aldehydes and ketones so esters are even less acidic. The most important reactions of ester enolates are the Claisen and Dieckmann cond Continue reading >>

Why Are Esters And Amides Weaker Carbon Acids Than Ketones And Acid Fluorides? Contributions By Resonance And Inductive Effects

Why Are Esters And Amides Weaker Carbon Acids Than Ketones And Acid Fluorides? Contributions By Resonance And Inductive Effects

Abstract Two computational methodologies—a vinylogue extrapolation methodology and a block localized wave function (BLW) methodology—were employed to determine the contributions by resonance and inductive effects toward the gas-phase deprotonation enthalpies at the α carbons of acetone, acetamide, acetic acid, and acetyl fluoride, which were taken to be model compounds for ketones, amides, esters, and acid fluorides, respectively. Results from the vinylogue methodology suggest that resonance serves to enhance the gas-phase deprotonation enthalpy of a ketone by 34.3 kcal/mol, an amide by 26.2 kcal/mol, an ester by 30.5 kcal/mol, and an acid fluoride by 30.8 kcal/mol. Comparably, the BLW methodology suggests those numbers to be 42.3, 31.2, 36.1, and 39.7 kcal/mol, respectively. Results from the vinylogue methodology suggest that inductive effects serve to enhance the gas-phase deprotonation enthalpy of a ketone by 11.8 kcal/mol, an amide by 12.7 kcal/mol, an ester by 15.5 kcal/mol, and an acid fluoride by 26.0 kcal/mol, and in the same order, those numbers suggested by the BLW methodology are 3.0, 6.2, 8.5, and 16.3 kcal/mol. Continue reading >>

Ketosis

Ketosis

There is a lot of confusion about the term ketosis among medical professionals as well as laypeople. It is important to understand when and why nutritional ketosis occurs, and why it should not be confused with the metabolic disorder we call ketoacidosis. Ketosis is a metabolic state where the liver produces small organic molecules called ketone bodies. Most cells in the body can use ketone bodies as a source of energy. When there is a limited supply of external energy sources, such as during prolonged fasting or carbohydrate restriction, ketone bodies can provide energy for most organs. In this situation, ketosis can be regarded as a reasonable, adaptive physiologic response that is essential for life, enabling us to survive periods of famine. Nutritional ketosis should not be confused with ketoacidosis, a metabolic condition where the blood becomes acidic as a result of the accumulation of ketone bodies. Ketoacidosis can have serious consequences and may need urgent medical treatment. The most common forms are diabetic ketoacidosis and alcoholic ketoacidosis. What Is Ketosis? The human body can be regarded as a biologic machine. Machines need energy to operate. Some use gasoline, others use electricity, and some use other power resources. Glucose is the primary fuel for most cells and organs in the body. To obtain energy, cells must take up glucose from the blood. Once glucose enters the cells, a series of metabolic reactions break it down into carbon dioxide and water, releasing energy in the process. The body has an ability to store excess glucose in the form of glycogen. In this way, energy can be stored for later use. Glycogen consists of long chains of glucose molecules and is primarily found in the liver and skeletal muscle. Liver glycogen stores are used to mai Continue reading >>

Ketoacidosis Versus Ketosis

Ketoacidosis Versus Ketosis

Some medical professionals confuse ketoacidosis, an extremely abnormal form of ketosis, with the normal benign ketosis associated with ketogenic diets and fasting states in the body. They will then tell you that ketosis is dangerous. Testing Laboratory Microbiology - Air Quality - Mold Asbestos - Environmental - Lead emsl.com Ketosis is NOT Ketoacidosis The difference between the two conditions is a matter of volume and flow rate*: Benign nutritional ketosis is a controlled, insulin regulated process which results in a mild release of fatty acids and ketone body production in response to either a fast from food, or a reduction in carbohydrate intake. Ketoacidosis is driven by a lack of insulin in the body. Without insulin, blood sugar rises to high levels and stored fat streams from fat cells. This excess amount of fat metabolism results in the production of abnormal quantities of ketones. The combination of high blood sugar and high ketone levels can upset the normal acid/base balance in the blood and become dangerous. In order to reach a state of ketoacidosis, insulin levels must be so low that the regulation of blood sugar and fatty acid flow is impaired. *See this reference paper. Here's a table of the actual numbers to show the differences in magnitude: Body Condition Quantity of Ketones Being Produced After a meal: 0.1 mmol/L Overnight Fast: 0.3 mmol/L Ketogenic Diet (Nutritional ketosis): 1-8 mmol/L >20 Days Fasting: 10 mmol/L Uncontrolled Diabetes (Ketoacidosis): >20 mmol/L Here's a more detailed explanation: Fact 1: Every human body maintains the blood and cellular fluids within a very narrow range between being too acidic (low pH) and too basic (high pH). If the blood pH gets out of the normal range, either too low or too high, big problems happen. Fact 2: The Continue reading >>

1. Nomenclature Of Aldehydes And Ketones

1. Nomenclature Of Aldehydes And Ketones

Aldehydes and ketones are organic compounds which incorporate a carbonyl functional group, C=O. The carbon atom of this group has two remaining bonds that may be occupied by hydrogen or alkyl or aryl substituents. If at least one of these substituents is hydrogen, the compound is an aldehyde. If neither is hydrogen, the compound is a ketone. The IUPAC system of nomenclature assigns a characteristic suffix to these classes, al to aldehydes and one to ketones. For example, H2C=O is methanal, more commonly called formaldehyde. Since an aldehyde carbonyl group must always lie at the end of a carbon chain, it is by default position #1, and therefore defines the numbering direction. A ketone carbonyl function may be located anywhere within a chain or ring, and its position is given by a locator number. Chain numbering normally starts from the end nearest the carbonyl group. In cyclic ketones the carbonyl group is assigned position #1, and this number is not cited in the name, unless more than one carbonyl group is present. If you are uncertain about the IUPAC rules for nomenclature you should review them now. Examples of IUPAC names are provided (in blue) in the following diagram. Common names are in red, and derived names in black. In common names carbon atoms near the carbonyl group are often designated by Greek letters. The atom adjacent to the function is alpha, the next removed is beta and so on. Since ketones have two sets of neighboring atoms, one set is labeled α, β etc., and the other α', β' etc. Very simple ketones, such as propanone and phenylethanone (first two examples in the right column), do not require a locator number, since there is only one possible site for a ketone carbonyl function. Likewise, locator numbers are omitted for the simple dialdehyde at t Continue reading >>

Ketone

Ketone

Not to be confused with ketone bodies. Ketone group Acetone In chemistry, a ketone (alkanone) /ˈkiːtoʊn/ is an organic compound with the structure RC(=O)R', where R and R' can be a variety of carbon-containing substituents. Ketones and aldehydes are simple compounds that contain a carbonyl group (a carbon-oxygen double bond). They are considered "simple" because they do not have reactive groups like −OH or −Cl attached directly to the carbon atom in the carbonyl group, as in carboxylic acids containing −COOH.[1] Many ketones are known and many are of great importance in industry and in biology. Examples include many sugars (ketoses) and the industrial solvent acetone, which is the smallest ketone. Nomenclature and etymology[edit] The word ketone is derived from Aketon, an old German word for acetone.[2][3] According to the rules of IUPAC nomenclature, ketones are named by changing the suffix -ane of the parent alkane to -anone. The position of the carbonyl group is usually denoted by a number. For the most important ketones, however, traditional nonsystematic names are still generally used, for example acetone and benzophenone. These nonsystematic names are considered retained IUPAC names,[4] although some introductory chemistry textbooks use systematic names such as "2-propanone" or "propan-2-one" for the simplest ketone (CH3−CO−CH3) instead of "acetone". The common names of ketones are obtained by writing separately the names of the two alkyl groups attached to the carbonyl group, followed by "ketone" as a separate word. The names of the alkyl groups are written alphabetically. When the two alkyl groups are the same, the prefix di- is added before the name of alkyl group. The positions of other groups are indicated by Greek letters, the α-carbon being th Continue reading >>

Why Is The Alpha Hydrogen On An Ester Less Acidic Than The Alpha Hydrogens Of Aldehydes Or Ketones? Shoudln't The The Two Carbonyl Oxygens Of The Ester Stabalize The Conjugate Base Making It Very Acidic When Protonated?

Why Is The Alpha Hydrogen On An Ester Less Acidic Than The Alpha Hydrogens Of Aldehydes Or Ketones? Shoudln't The The Two Carbonyl Oxygens Of The Ester Stabalize The Conjugate Base Making It Very Acidic When Protonated?

Here you can see the deprotonation of acetone and acetaldehyde, respectively. For acetone and acetaldehyde specifically, the explanation is simply that the substituent on acetone is larger than on acetaldehyde (CH3 vs. H). The larger the substituents attached, the more electron-electron repulsion the deprotonated other carbon has with the carbonyl oxygen (larger substituent, more steric strain from orbital crowding, more repulsion). Their resonance structures are identical aside from those two substituents as the difference. Similarly, here you can see the enolate of methyl acetate: For methyl acetate vs. acetone specifically, besides the substituent size, knowing how it has two competing resonance structures (deprotonated carbon with carbonyl vs. the alkoxyl oxygen with the carbonyl), if we look at the oxygen-oxygen resonance structure, the alkoxyl oxygen stabilizes the carbonyl. But that leaves the δ− carbon less likely to stabilize with the carbonyl oxygen due to similar partial charges, lessening the amount of possible resonance stabilization. Continue reading >>

Why Are Aldehydes And Ketones Neutral And Not Acidic/basic?

Why Are Aldehydes And Ketones Neutral And Not Acidic/basic?

This question is quite general, and as other answers have pointed out, depends on what you mean by acidic/basic. The other answers have already covered the Lewis bit, so I will focus a bit more on the Bronsted-Lowry and Arrhenius definitions. In water, almost all aldehydes and ketones do not dissociate to give the H+ or OH- ion, which is the Arrhenius definition. However, the alpha position of acetylacetone is considered acidic by the Bronsted-Lowry definition, and can be deprotonated by strong bases to give the conjugated enone after tautomerism. This is due to the stability of the conjugate base. Continue reading >>

The Alkaline Diet Vs Acidic Ketones

The Alkaline Diet Vs Acidic Ketones

Whether you think eating alkaline foods is useful or woo woo junk it appears that metabolic acidosis is a thing. Metabolic acidosis seems to be interrelated with insulin resistance, Type 2 Diabetes, and retention of muscle mass. To prevent metabolic acidosis, it appears prudent to ensure that your body has adequate minerals to enable your kidneys to balance pH over the long term. This can be achieved by eating plenty of veggies and/or supplementing with alkaline minerals (e.g. magnesium, sodium, potassium, zinc etc). If you eat plenty of veggies you’re probably getting enough alkalising minerals, however, you can easily test your urine to see if your dietary acid load is high. If you are targeting a high fat therapeutic ketogenic diet, following a zero-carb dietary approach and/or taking exogenous ketones it seems then it may be even more important to be mindful of your acid load and consider mineral supplementation. Recently I had a fascinating, surprising and exciting experience during a fast. The chart below shows my ketones, glucose and ‘total energy’ (i.e. glucose plus ketones) over the seven days. My ketones increased to above 8.0 mmol/L. They even couldn’t be read on my ketone metre! It was the full keto brochure experience. It was like my body fat was effortlessly feeding my brain with delicious, succulent ketones! I felt great. This chart shows my glucose : ketone index (GKI) dropping to below 0.5 after a few days. The orange dots in this chart shows the relationship between glucose and ketones about 18 months ago when I first started trying this keto thing (after I read ‘Jimmy’s Moore’s Keto Clarity’). The blue dots show the relationship between my glucose and ketones during the recent fast. As you can see from the much flatter line, my blood g Continue reading >>

Is A Ketone An Acid Or A Base?

Is A Ketone An Acid Or A Base?

Ketones are in fact weak acids. This comes from an ability to shift the places of the double bond and one of the hydrogen atoms, resulting in an alcohol compound with a double bond between two of the carbon atoms. This is called an enol, and is less stable than the ketone - the two are in rapid equilibrium. This enol may lose a hydrogen ion to become an enolate. This happens only when a ketone is reacted with a strong base. Continue reading >>

Enolate Formation From Ketones

Enolate Formation From Ketones

Voiceover: In order to see how to form enolate anions, and in this video we're just gonna look in more detail how to form enolate anions from ketones. And so the ketone we have here is acetone. To find our alpha carbon, we just look at the carbon next to our carbonyl carbon, so this could be an alpha carbon, and this could be an alpha carbon. Each one of those alpha carbons has three alpha protons, and so there's a total of six. I'm just gonna draw one in here, and this is the one that we're going to show being deprotonated here. So, the base that's going to deprotonate acetone, we're gonna use LDA, which is Lithium Diisopropyl Amide And, I could go ahead and draw in the Lithium here, so Li Plus, and then we see the two isopropyl groups like that, a negative one charge on our nitrogen. So this is a very strong base, it's also very bulky and sterically hindered. So you can think about a lone pair of electrons in the nitrogen, taking that proton, leaving these electrons behind on this carbon, so we can go ahead and draw the conjugate base here. We would have electrons on this carbon now, that's a carbanion, so let me go ahead and show those electrons, these electrons in here magenta, are gonna come off onto this carbon. And this carbon is a [carbanae] because remember there's also two other hydrogens attached to it. So that's what gives it a negative one formal charge here. We can draw our resonance structure, we can show these electrons in magenta moving in here, these electrons coming off onto our oxygen, so for our resonance structure we would show the negative charge is now on our oxygen, this would be a negative one formal charge like that now. So the electrons in magenta moved into here to form our double bond, and then we can show the electrons in here in the blue Continue reading >>

Urine Test Types: Ph, Ketones, Proteins, And Cells

Urine Test Types: Ph, Ketones, Proteins, And Cells

Urine as a Diagnostic Tool A long time ago, disgusting as it may be, people used to actually taste and drink urine in order to try and diagnose a patient's disease! I'm not even kidding you. Thankfully, modern-day doctors do not have to resort to such disgusting and even dangerous methods. One of the reasons the doctor barbers of yesteryear used to drink their patient's urine was to see if it had a sweet taste, often indicative of diabetes mellitus. Finding the sweet-tasting glucose in the urine was covered in detail in another lesson, so we'll focus on other important measurements here instead. Interpreting Urine pH One value that can be measured in the urine is known as urine pH. pH is a measure of the acidity or alkalinity of a substance. If the pH is low, then it is acidic. If the pH is high, then it is basic, or alkaline. To remember which is which, I'll give you a little trick that has worked for me. If you grew up watching cartoons, you probably saw some comical ones where cartoonish robbers poured acid on the roof of a bank vault and waited while the acid ate its way downward into the vault, so the robbers could get down there to steal all the cash. If you can recall that acid likes to eat its way downward into things, then you'll remember that acidic substances go down the pH scale. That is to say, their pH numbers are lower than basic substances. Normal urine pH is roughly 4.6-8, with an average of 6. Urine pH can increase, meaning it will become more basic, or alkaline, due to: A urinary tract infection Kidney failure The administration of certain drugs such as sodium bicarbonate Vegetarian diets On the flip side, causes for a decreased, or acidic, urine pH, include: Metabolic or respiratory acidosis Diabetic ketoacidosis, a complication of diabetes mellitus Continue reading >>

Aldehydes, Ketones, Carboxylic Acids, And Esters

Aldehydes, Ketones, Carboxylic Acids, And Esters

Learning Objectives By the end of this section, you will be able to: Describe the structure and properties of aldehydes, ketones, carboxylic acids and esters Another class of organic molecules contains a carbon atom connected to an oxygen atom by a double bond, commonly called a carbonyl group. The trigonal planar carbon in the carbonyl group can attach to two other substituents leading to several subfamilies (aldehydes, ketones, carboxylic acids and esters) described in this section. Aldehydes and Ketones Both aldehydes and ketones contain a carbonyl group, a functional group with a carbon-oxygen double bond. The names for aldehyde and ketone compounds are derived using similar nomenclature rules as for alkanes and alcohols, and include the class-identifying suffixes –al and –one, respectively: In an aldehyde, the carbonyl group is bonded to at least one hydrogen atom. In a ketone, the carbonyl group is bonded to two carbon atoms: In both aldehydes and ketones, the geometry around the carbon atom in the carbonyl group is trigonal planar; the carbon atom exhibits sp2 hybridization. Two of the sp2 orbitals on the carbon atom in the carbonyl group are used to form σ bonds to the other carbon or hydrogen atoms in a molecule. The remaining sp2 hybrid orbital forms a σ bond to the oxygen atom. The unhybridized p orbital on the carbon atom in the carbonyl group overlaps a p orbital on the oxygen atom to form the π bond in the double bond. Like the C=O bond in carbon dioxide, the C=O bond of a carbonyl group is polar (recall that oxygen is significantly more electronegative than carbon, and the shared electrons are pulled toward the oxygen atom and away from the carbon atom). Many of the reactions of aldehydes and ketones start with the reaction between a Lewis base and Continue reading >>

22.3 Alpha Halogenation Of Aldehydes And Ketones

22.3 Alpha Halogenation Of Aldehydes And Ketones

Objectives After completing this section, you should be able to write an equation to illustrate the alpha halogenation of aldehydes and ketones. identify the product formed from the alpha halogenation of a given aldehyde or ketone. identify the carbonyl compound, the reagents, or both, needed to prepare a given α‑halogenated aldehyde or ketone. illustrate the importance of the alpha halogenation of carbonyl compounds as an intermediate step in the synthesis of α,β‑unsaturated aldehydes and ketones. write a detailed mechanism for the acid‑catalyzed halogenation of a ketone. describe the evidence provided by kinetic experiments supporting the suggestion that the acid‑catalyzed, alpha halogenation of ketones proceeds via the rate‑determining formation of an enol. Study Notes Note: α‑bromo ketones are a good starting material to generate α,β‑unsaturated ketones by dehydrobromination. A carbonyl containing compound with α hydrogens can undergo a substitution reaction with halogens. This reaction comes about because of the tendency of carbonyl compounds to form enolates in basic condition and enols in acidic condition. In these cases even weak bases, such as the hydroxide anion, is sufficient enough to cause the reaction to occur because it is not necessary for a complete conversion to the enolate. For this reaction Cl2, Br2 or I2 can be used as the halogens. General reaction Under acidic conditions the reaction occurs thought the formation of an enol which then reacts with the halogen. 1) Protonation of the carbonyl 2) Enol formation 3) SN2 attack 4) Deprotonation Kinetic studies provide some evidence for the mechanism shown above. The rate law for the alpha-halogenation of a ketone can be given by: rate = [ketone][H+] The implication is that the rate de Continue reading >>

More in ketosis