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How Are Ketones Named

Ketones

Ketones

Abstract As already mentioned in Chapter 20, which deals with aldehydes, compounds containing the carbonyl group (>C=O, commonly written CO) attached to two carbon atoms are called ketones. In that chapter the close structural relationship between aldehydes and ketones is pointed out, and the need in systematic nomenclature to distinguish between these two types of carbonyl compounds is questioned. Nevertheless, since modern usage continues to reflect the desire of organic chemists to treat aldehydes and ketones as two separate functional classes and since no official approval has yet been given to proposals for a unified nomenclature, the traditional approach is retained in this book. Also included in this chapter are thioketones, which contain the thiocarbonyl group (>C=S), and quinones, which are a sub-class made up of cyclic unsaturated ketones having two carbonyl groups directly attached to a six-membered ring containing two double bonds. Structures in which an ester, amide, or anhydride Continue reading >>

Organic Chemistry/naming

Organic Chemistry/naming

There are thousands of known organic compounds and millions of others yet to be discovered. Because of the wide variety of compounds a naming system was developed by International Union of Pure and Applied Chemistry (IUPAC)[1] to give a unique descriptive name to each compound. In this system the name of the compound directly shows its structure through an elaborate system of suffixes and prefixes. Common names are used for compounds that were either around before IUPAC or who have a more widely known name than the IUPAC. For example, trichloromethane is IUPAC name for chloroform, though it is almost universally referred to by students and scientists alike as chloroform. 1 Naming parent chains The IUPAC nomenclature of organic molecules is based on the longest carbon chain in the molecule. For alliphatics, which are hydrocarbons containing chains of C, the following prefixes are used: # of C Stem name Alkyl group name 1 meth methyl 2 eth ethyl 3 prop propyl 4 but butyl 5 pent pentyl 6 hex hexyl 7 hept heptyl 8 oct octyl 9 non nonyl 10 dec decyl 11 undec undecyl 12 dodec dodecyl Alkanes are a compound in which the carbon backbone contains only single bonds. They are named according to the number of carbons they have. Alkanes combust to produce water and carbon dioxide in air. Some familiar alkanes are methane (natural gas), propane (gas used in homes), and butane (blue-flamed cigarette lighters). Alkanes containing four carbons or more can form different chain isomers; that is, they can become "branched," forming, for example, iso-butane. General Alkane Formula: CnH2n+2 Suffix: "ane" Example: CH3CH2CH3 - Propane To name branched molecules, find the longest continuous chain first. This chain forms the base name. Number the carbon atoms, starting at the end closest to the Continue reading >>

Reactions Of Aldehydes And Ketones

Reactions Of Aldehydes And Ketones

Aldehydes and ketones undergo a variety of reactions that lead to many different products. The most common reactions are nucleophilic addition reactions, which lead to the formation of alcohols, alkenes, diols, cyanohydrins (RCH(OH)C&tbond;N), and imines R 2C&dbond;NR), to mention a few representative examples. The main reactions of the carbonyl group are nucleophilic additions to the carbon‐oxygen double bond. As shown below, this addition consists of adding a nucleophile and a hydrogen across the carbon‐oxygen double bond. Due to differences in electronegativities, the carbonyl group is polarized. The carbon atom has a partial positive charge, and the oxygen atom has a partially negative charge. Aldehydes are usually more reactive toward nucleophilic substitutions than ketones because of both steric and electronic effects. In aldehydes, the relatively small hydrogen atom is attached to one side of the carbonyl group, while a larger R group is affixed to the other side. In ketones, however, R groups are attached to both sides of the carbonyl group. Thus, steric hindrance is less in aldehydes than in ketones. Electronically, aldehydes have only one R group to supply electrons toward the partially positive carbonyl carbon, while ketones have two electron‐supplying groups attached to the carbonyl carbon. The greater amount of electrons being supplied to the carbonyl carbon, the less the partial positive charge on this atom and the weaker it will become as a nucleus. The addition of water to an aldehyde results in the formation of a hydrate. The formation of a hydrate proceeds via a nucleophilic addition mechanism. 1. Water, acting as a nucleophile, is attracted to the partially positive carbon of the carbonyl group, generating an oxonium ion. Acetal formation reacti Continue reading >>

Aldehydes And Ketones

Aldehydes And Ketones

Can you resist the smell of a fresh baked cinnamon bun? There’s nothing like the smell of a fresh cinnamon roll. The taste is even better. But what causes that delicious taste? This flavoring comes from the bark of a tree (actually, several different kinds of trees). One of the major compounds responsible for the taste and odor of cinnamon is cinnamaldehyde. Cinnamon has been widely used throughout the centuries to treat a number of different disorders. In ancient times, doctors believed it could cure snakebite poisoning, freckles, and the common cold. Today there are several research studies being carried out on the health benefits of cinnamon. So, enjoy that cinnamon roll – it just might be good for you. Aldehydes and Ketones Aldehydes and ketones are two related categories of organic compounds that both contain the carbonyl group, shown below. The difference between aldehydes and ketones is the placement of the carbonyl group within the molecule. An aldehyde is an organic compound in which the carbonyl group is attached to a carbon atom at the end of a carbon chain. A ketone is an organic compound in which the carbonyl group is attached to a carbon atom within the carbon chain. The general formulas for each are shown below. For aldehydes, the R group may be a hydrogen atom or any length carbon chain. Aldehydes are named by finding the longest continuous chain that contains the carbonyl group. Change the –e at the end of the name of the alkane to –al. For ketones, R and R’ must be carbon chains, of either the same or different lengths. The steps for naming ketones, followed by two examples, are shown below. Name the parent compound by finding the longest continuous chain that contains the carbonyl group. Change the –e at the end of the name of the alkane t Continue reading >>

14.9 Aldehydes And Ketones: Structure And Names

14.9 Aldehydes And Ketones: Structure And Names

Learning Objectives Identify the general structure for an aldehyde and a ketone. Use common names to name aldehydes and ketones. Use the IUPAC system to name aldehydes and ketones. The next functional group we consider, the carbonyl group, has a carbon-to-oxygen double bond. Carbonyl groups define two related families of organic compounds: the aldehydes and the ketones. Note The carbonyl group is ubiquitous in biological compounds. It is found in carbohydrates, fats, proteins, nucleic acids, hormones, and vitamins—organic compounds critical to living systems. In a ketone, two carbon groups are attached to the carbonyl carbon atom. The following general formulas, in which R represents an alkyl group and Ar stands for an aryl group, represent ketones. In an aldehyde, at least one of the attached groups must be a hydrogen atom. The following compounds are aldehydes: In condensed formulas, we use CHO to identify an aldehyde rather than COH, which might be confused with an alcohol. This follows the general rule that in condensed structural formulas H comes after the atom it is attached to (usually C, N, or O). The carbon-to-oxygen double bond is not shown but understood to be present. Because they contain the same functional group, aldehydes and ketones share many common properties, but they still differ enough to warrant their classification into two families. 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 >>

Ketone

Ketone

Previous (Kermit Roosevelt, Jr.) Next (Key (music)) A ketone (pronounced as key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. A ketone can be generally represented by the formula: A carbonyl carbon bonded to two carbon atoms distinguishes ketones from carboxylic acids, aldehydes, esters, amides, and other oxygen-containing compounds. The double-bond of the carbonyl group distinguishes ketones from alcohols and ethers. The simplest ketone is acetone (also called propanone). Mold Test Kits Easy to Use, Fast Results Available Interpretive Lab Report moldtesting.com The carbon atom adjacent to a carbonyl group is called the α-carbon. Hydrogens attached to this carbon are called α-hydrogens. In the presence of an acid catalyst the ketone is subjected to so-called keto-enol tautomerism. The reaction with a strong base gives the corresponding enolate. A diketone is a compound containing two ketone groups. Nomenclature In general, ketones are named using IUPAC nomenclature by changing the suffix -e of the parent alkane to -one. For common ketones, some traditional names such as acetone and benzophenone predominate, and these are considered retained IUPAC names,[1] although some introductory chemistry texts use names such as propanone. Oxo is the formal IUPAC nomenclature for a ketone functional group. However, other prefixes are also used by various books and journals. For some common chemicals (mainly in biochemistry), keto or oxy is the term used to describe the ketone (also known as alkanone) functional group. Oxo also refers to a single oxygen atom coordinated to a transition metal (a metal oxo). Physical properties A carbonyl group is polar. This ma Continue reading >>

Organic Chemistry- Aldehydes And Ketones I Flashcards Preview

Organic Chemistry- Aldehydes And Ketones I Flashcards Preview

The carbonyl group First carbonyl is a component of many different functional groups (carboxylic acid, ester, amides, anhydrides) The carbonyl has the unique ability to behave as either a nucleophile (as in condensation reactions) or an electrophile (as in nucleophilic addition reactions) Continue reading >>

Functional Group Names, Properties, And Reactions

Functional Group Names, Properties, And Reactions

Functional Groups Functional groups refer to specific atoms bonded in a certain arrangement that give a compound certain physical and chemical properties. Learning Objectives Define the term “functional group” as it applies to organic molecules Key Takeaways Functional groups are often used to “functionalize” a compound, affording it different physical and chemical properties than it would have in its original form. Functional groups will undergo the same type of reactions regardless of the compound of which they are a part; however, the presence of certain functional groups within close proximity can limit reactivity. Functional groups can be used to distinguish similar compounds from each other. functional group: A specific grouping of elements that is characteristic of a class of compounds, and determines some properties and reactions of that class. functionalization: Addition of specific functional groups to afford the compound new, desirable properties. The Role of Functional Groups In organic chemistry, a functional group is a specific group of atoms or bonds within a compound that is responsible for the characteristic chemical reactions of that compound. The same functional group will behave in a similar fashion, by undergoing similar reactions, regardless of the compound of which it is a part. Functional groups also play an important part in organic compound nomenclature; combining the names of the functional groups with the names of the parent alkanes provides a way to distinguish compounds. The atoms of a functional group are linked together and to the rest of the compound by covalent bonds. The first carbon atom that attaches to the functional group is referred to as the alpha carbon; the second, the beta carbon; the third, the gamma carbon, etc. Simi Continue reading >>

Naming Ketones

Naming Ketones

Ketones are organic chemical compounds that include a -carbonyl group (i.e. an oxygen atom attached to a carbon atom by a double covalent bond) such that the carbon atom to which the -carbonyl group is attached is itself attached to two other carbon atoms - as opposed to one other carbon atom and one hydrogen atom, which the case for aldehydes That is, ketones are a class or category of organic chemical compounds that include a carbon atom attached to both an oxygen atom (by a double covalent bond), and also to two other carbon atoms (by a single covalent bond in each case). Bearing in mind that carbon atoms form a total of 4 single covalent bonds - or equivalent in combinations of double or triple bonds, a carbon atom attached to both an oxygen atom (by a double covalent bond) and also to two other carbon atoms (by a single covalent bond in each case) cannot be the first- or last - (which are equivalent positions) carbon atom in the chain of carbon atoms that form the organic molecule of which it is a part. This position of the -carbonyl group (oxygen atom) attached to a carbon atom that is not the last carbon atom in a carbon-chain is important because it distinguishes ketones from a similar category of organic compounds, called aldehydes. In contrast to ketones, aldehydes include a -carbonyl group attached to the end-carbon in a carbon-chain. Ketone molecules can vary in size up to very long molecules most of which consist of carbon atoms attached to each other and also to hydrogen atoms. Continue reading >>

Nomenclature

Nomenclature

IUPAC Names The naming of ketones is actually fairly simple, if you use the IUPAC method. It is very similar to the naming of alcohols. You start by choosing the longest carbon chain you can find that includes the carbon from the carbonyl group and use the length of that carbon chain as your base name. You change the ending by removing the -e and adding -one, and adding a number at the beginning of the name to indicate which carbon is double bonded to the oxygen. Then, if there are any side groups attached to the main chain, those are added to the front of the name with the appropriate numbers to show their location. Example A specific example is shown here (from Example 12-b in your workbook): butanone is formed from 2-butanol. The carbon chain is four carbon atoms long. Therefore, we have "butane" as a starting point. One of those carbons is double bonded to an oxygen. This make the compound a ketone. This means that we replace the -e ending on the "butane" with an -one ending to get butanone. (We could also use a 2- in front of this name to indicate that it is the 2nd carbon which is a member of the carbonyl group. This gives the name 2-butanone for this particular compound. However, the 2- is unnecessary here since if the carbonyl group were to be moved one carbon to the right we would start numbering from the right side of the compound and that carbon would be #2.) H H H | | | H-C-C-C-C-H | || | | H O H H butanone In this example I would also like to point out that the alcohol we start with, and the ketone we end up with both have the same number of carbon atoms. In addition, the carbonyl group in the ketone is in the same location as the hydroxyl group in the alcohol. This is a very important consideration when you are trying to make a particular ketone. You need Continue reading >>

Organic Nomenclature

Organic Nomenclature

This document contains a highly compressed, simplified version of the naming rules put out by the International Union on Pure and Applied Chemistry (IUPAC). That's right, I said simplified. The actual rules must cover perfectly accurately all 20 million or so compounds discovered to date, and all 10 million or so that we will discover over the next decade or so. They are mind-bogglingly complex (to steal a phrase from Douglas Adams). The rules here are intended to work well on simple compounds, and to give the introductory student a flavor for how the system works. The naming of a compound follows several basic steps: Identify the functional groups present and assign them priority. Identify the highest priority substituent. Identify a parent portion of the molecule; name and number it. Identify the substituents and locate them on the numbered parent Assemble the name in proper order, and with proper punctuation, etc. Identify Functional Groups and Assign Priority The first step is to identify the functional groups present in the molecule. The following table has a large number of functional groups ranked in priority order. You should know that the highest priority group in your compound (towards the top of the table) is treated differently from the rest of the functional groups in the molecule. Note that some functional groups appear to have two or more carbon-containing groups; be sure you pay attention to which side of the functional group is the "main" side and which is the secondary side. For example, the "main" part of the ester group as shown below contains the R group; the secondary side contains the R' group. The main part of the functional group will be included in the parent. Carboxylic acid -oic acid* propanoic acid propionic acid Salt of acid -oate* sodium e Continue reading >>

Try To Name The Following Compound Using These Conventions�

Try To Name The Following Compound Using These Conventions�

a. Ketones are named by dropping the -e ending of the parent name and adding -one. The substituent name for the O= group is oxo. Ketones can also be named by naming each of the two carbon groups as a separate word followed by a space and the word ketone. b. Ring compounds can be named by dropping the -e ending of the parent name and adding -one. c. Common names that you should know are... d. The Greek letters a, b, g, etc. are used at times to designate attached groups on the second, third and fourth, etc. carbons from the carbonyl. This nomenclature is common for many functional groups such as aldehydes, carboxylic acids and derivatives of carboxylic acids. Copyright � August 2000 by Richard C. Banks...all rights reserved. Continue reading >>

Weird Nomenclature In Carbonyl Chemistry

Weird Nomenclature In Carbonyl Chemistry

Making it through the chemistry of carbonyl derivatives (ketones, aldehydes, carboxylic acids, esters, and more) there are at least two “weird” nomenclature issues that repeatedly come up to baffle students: Greek letters, and “1,2-” or “1,4-” addition reactions. In this post I’ll try to address them both. 1. Greek letters The functional group C=O is called a “carbonyl”. The carbon itself is called the “carbonyl carbon”, and the oxygen is called “the carbonyl oxygen”. But what do you call a carbon adjacent to the carbonyl carbon… or 3 carbons away? In organic chemistry, it’s common to use Greek letters to denote this. So the carbon adjacent to a carbonyl is called an “α (alpha) carbon”, two carbons away is called a “β carbon”, and so on. This nomenclature can be used to depict different kinds of substituted carbonyl groups. For example a ketone with an OH on the beta carbon would be called a “β-hydroxy ketone”. If it was one carbon further down it would be a “γ hydroxy ketone”. If we have a double bond between the α carbon and the β carbon it’s common to call it “α,β-unsaturated”. So we can have α,β unsaturated ketones, aldehydes, esters, and so on. It can keep going beyond gamma, of course, but it’s rare to see it progress beyond ε (epsilon). Another thing: aldehydes, esters, carboxylic acids, and so on, can only have one “alpha” carbon each, wheras ketones can have two. Sometimes you’ll see one set of Greek symbols marked with ‘ (prime) symbols to distinguish them. The location of the prime is completely arbitrary. For esters, the OR group is not denoted “alpha”. It’s usually just called the “alkoxy” group. 1,2 and 1,4 additions Another item of confusion are the terms “1,2-addition” Continue reading >>

Ll.l Aldehydes Ond Ketones

Ll.l Aldehydes Ond Ketones

Focus l3.l Aldehydes and Ketones 595 AIM: To describe the corbon-oxygen bond of the corbonyl group of oldehydes ond ketones. The functional group known as the carbonyl group ( )C-O)-a carbon ato m and an oxy gen atonx j o ined by a double b o nd-is fciund in comp ounds called aldehydes arrd ketones. Structures of aldehydes and ketones Aldehydes are organic compounds in which the carbonyl carbon-the car- bon to which the oxygen k bonded-is always joined to at least one hydro- gen.The general formula for an aldehyde is Carbonr.l. ox'gen \ t O - ^ - L ^ - . | - - ^ . . - 1a---zCatbonvl grouP R-C-H I Carbonyl / carbon This structural formula is often abbreviated to RCHO. Ketones are organic compounds in which the carbonyl carbon is joined to two other carbons: Carbonrtl. orygen \ O - ^ * L ^ . ^ , , r ^ - ^ , . ^ !1 <-_-- CarA on1'l group R-C-R ,( Carbonyl/ carbon The abbreviated form for a ketone is RCOR. Note the similarity in structure of aldehydes and ketones. Because they both contain the carbonyl group, the chemistry of aldehydes and ketones is similar. Both aldehydes and ketones are highly reactive, but aldehydes are generally the more reactive of the two classes. Namtng aldehydes and ketones The IUPAC system may be used for naming aldehydes. We must first identify the longest hydrocarbon chain that contains the carbonyl car- bon. The -e ending of the hydrocarbon is replace dby -al to designate an aldehyde. Using the IUPAC system, we name the aldehydes methanal, ethanal, propanal, butanal, and so forth. In naming substituted aldehy- des, the longest chain is counted starting from the carbon of the alde- hyde group. The general structures of aldehydes and ketones are similar. ,94 CHAPTER 13 Aldehydes and Ketones I X A M P L E I 5 . I Naming a substituted aldehyde by t Continue reading >>

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