CH. 11-15 part 2

Chapter 14 Carboxylic Acids, Esters, Amines, and Amides 14.3 Esters

Esters Esters are found in fats and oils responsible for the aroma and flavor of bananas, oranges, and strawberries O  CH3 —C—O—CH3 ester group

Esterification Esterification is the reaction of a carboxylic acid and alcohol in the presence of an acid catalyst to produce an ester. The main chain of an ester comes from the carboxylic acid, while the alkyl group in an ester comes from the alcohol.

Esterification An example of esterification is the reaction of a ethanoic acid with 1-propanol to produce an ester called propylethanoate, responsible for the smell of pears.

Naming Esters Esters have IUPAC and common names:

Learning Check Give the IUPAC and common names of the following compound, which is responsible for the flavor and odor of pears. O  CH3 — C—O—CH2—CH2—CH3

Aspirin and Salicylic Acid is used to relieve pain and reduce inflammation is an ester of salicylic acid and acetic acid Oil of wintergreen is used to soothe sore muscles is an ester of salicylic acid and methanol

Esters in Fruits Esters give pleasant fragrances and flavors to many fruits and flowers.

Solution A. 3-bromobutanoic acid Br O | || CH3—CH—CH2—COH B. ethyl propionoate O  CH3—CH2 —C—O—CH2—CH3

Base Hydrolysis of Fatty Acids Produces Soaps

Cleaning Action of Soap A soap contains a nonpolar end that dissolves in nonpolar fats and oils, and a polar end that dissolves in water forms groups of soap molecules called micelles that dissolve in water and are washed away

Chapter 14 Carboxylic Acids, Esters, Amines, and Amides 14.4 Amines

Amines Amines are derivatives of ammonia, NH3 contain N attached to one or more alkyl or aromatic groups CH3 CH3   CH3—NH2 CH3—NH CH3—N—CH3

Classification of Amines Amines are classified as primary, secondary, or tertiary: a primary (1) amine has one carbon group bonded to the nitrogen atom a secondary (2) amine has two carbon groups bonded to the nitrogen atom a tertiary (3) amine has three carbon groups bonded to the nitrogen atom H CH3 CH3 | | | CH3—N—H CH3—N—H CH3—N—CH3 1° 2° 3°

Skeletal Structures of Amines The skeletal structures show the shapes of amine molecules with one or more alkyl groups bonded to the nitrogen atom.

Naming Amines Simple amines are named as alkylamines list the names of the alkyl groups bonded to the N atom in alphabetical order in front of amine CH3—CH2—NH2 Ethylamine CH3—NH—CH3 Dimethylamine CH3 | CH3—N—CH2—CH3 Ethyldimethylamine

Learning Check Give the common name of each compound. A. CH3—NH—CH2—CH3 CH3 | B. CH3—CH2—N—CH2—CH3 C.

Properties of Amines 1 and 2 amines can form hydrogen bonds with each other and water molecules can form hydrogen bonds, while amines with less than six carbons are soluble in water because they form hydrogen bonds with water 3 amines can only form hydrogen bonds with water molecules

Learning Check Consider the compounds below: 1. Which compound cannot form hydrogen bonds with other amines? 2. Which compound is not soluble in water? A. CH3—CH2—CH2—NH2 B. CH3—CH2—NH—CH3 C. CH3—CH2—CH2—CH3

Solution Consider the compounds below: 1. Which compound cannot form hydrogen bonds with other amines? CH3—CH2—CH2—CH3 C is an alkane, which cannot form hydrogen bonds with each other. 2. Which compound is not soluble in water? CH3—CH2—CH2—CH3 C is an alkane and therefore not soluble in water.

Neutralization Forms Amine Salts An amine salt forms when amines such as those responsible the odor in fish are neutralized by acid such as citric acid in lemons is named by replacing the amine part of the name with ammonium, followed by the name of the negative ion

Neutralization Forms Amine Salts

Properties of Amine Salts Amine salts are solids at room temperature soluble in water and body fluids the form used for drugs

Alkaloids Alkaloids are physiologically active nitrogen-containing compounds produced by plants such as cocaine compounds that are alkali-like or have basic characteristics like amines used as anesthetics, as antidepressants, and in stimulants such as caffeine, and may be habit forming

Alkaloids: Cocaine Cocaine is extracted from plants by reacting them with hydrochloric acid and producing cocaine hydrochloride. When cocaine hydrochloride is treated with NaOH and ether it is called free-basing. This reaction produces “crack cocaine,” a free amine or free base of the amine.

Heterocyclic Amines A heterocyclic amine is a cyclic compound that contains one or more nitrogen atoms in a ring typically consists of five or six atoms in the ring with one or more nitrogen atoms

Caffeine Caffeine is a stimulant of the central nervous system is found in coffee beans, tea, chocolate, and soft drinks

Nicotine Nicotine increases the adrenaline level in the blood causes addiction to tobacco

Morphine and Codeine Morphine and codeine are alkaloids obtained from the oriental poppy plant used as painkillers modified to make heroin

Solution A. methylpropylamine CH3–CH2–CH2–NH–CH3 B. 2-chloroaniline

Chapter 14 Carboxylic Acids, Esters, Amines, and Amides

Amides Amides are derivatives of carboxylic acids in which a nitrogen group (–NH2) replaces the –OH group of carboxylic acids. O O || || CH3—C—OH CH3—C—NH2

Preparation of Amides Amides are produced by reacting a carboxylic acid with ammonia or a 1 or 2 amine with heat.

Naming Amides For IUPAC naming, the -oic acid from the carboxylic acid name ending is replaced with -amide For common names, the -ic acid from the carboxylic acid name ending is replaced with -amide O  methanamide (IUPAC) H—C—NH2 formamide (common)  propanamide (IUPAC) CH3—CH2—C—NH2 propionamide (common)

Naming Amides with N Groups An alkyl group attached to the nitrogen of an amide is named with the prefix N-, followed by the alkyl name. O H  │ CH3 —C—N—CH3 N-methylethanamide (IUPAC) N-methylacetamide (common) O H CH3—CH2 —C—N—CH2—CH3 N-ethylpropanamide (IUPAC) N-ethylpropionamide (common)

Solution A. pentanamide O  CH3–CH2–CH2–CH2–C–NH2 B. N-methylbutyramide CH3–CH2–CH2–C–NH–CH3

Some Amides in Health and Medicine Urea is the end product of protein metabolism. Saccharin is an artificial sweetener. Some amides, such as phenobarbital (Luminal) and pentobarbital (Nembutal), are barbiturates. Acetaminophen is used to reduce fever and pain.

Some Amides in Health and Medicine

Solubility of Amides Amides with one to five carbon atoms are soluble in water because they can form hydrogen bonds with water molecules. Hydrogen bonding effects are diminished when molecules have more than five carbon atoms, therefore reducing solubility.

Hydrolysis Reactions

Chapter 15 Lipids 15.1 Lipids

Lipids Lipids are biomolecules that contain fatty acids or a steroid nucleus soluble in organic solvents, but not in water named for the Greek word lipos, which means “fat” extracted from cells using organic solvents an important feature in cell membranes, fat-soluble vitamins, and steroid hormones

Types of Lipids There are different types of lipids. 1. Lipids such as waxes, fats, oils, and glycerophospholipids are esters that can be hydrolyzed to give fatty acids and alcohols. 2. Steroids are also lipids; they do not contain fatty acids and cannot be hydrolyzed. They are characterized by the steroid nucleus of four fused carbon rings.

General Structure of Lipids Lipids are naturally occurring compounds that are soluble in organic solvents but not in water.

Learning Check There are two types of lipids, fatty acids and steroids. Which type is described by the following? A. contains a four-membered ring system B. contains long carbon chains C. includes triacylglycerols

Solution There are two types of lipids, fatty acids and steroids. Which type is described by the following? A. contains a four-membered ring system steroids B. contains long carbon chains fatty acids C. includes triacylglycerols fatty acids

Learning Check Which of the following is NOT a characteristic of lipids? A. may contain a carboxylic acid group B. may contain a four-ring structure C. soluble in water D. mostly nonpolar

Solution Which of the following is NOT a characteristic of lipids? The answer is C. Lipids are nonpolar and therefore are NOT soluble in water.

Chapter 15 Lipids 15.2 Fatty Acids

Fatty Acids Fatty acids are long-chain carboxylic acids typically 12–18 carbon atoms insoluble in water saturated or unsaturated Olive oil contains 84% unsaturated fatty acids and 16% saturated fatty acids.

Saturated and Unsaturated Fatty Acids Fatty acids can be saturated, with all single C–C bonds monounsaturated, with one double C=C bond polyunsaturated, with more than one double C=C bond

Properties of Saturated Fatty Acids contain only single C–C bonds and fit close together in a regular pattern have strong attractions between long carbon chains have higher melting points and are usually solids at room temperature

Properties of Saturated Fatty Acids In saturated fatty acids, the molecules fit closely together to give high melting points.

Properties of Unsaturated Fatty Acids contain one or more cis double C=C bonds have “kinks” in the fatty acid chains do not pack closely have few attractions between chains have low melting points are liquids at room temperature “kinks” in chain

Properties of Unsaturated Fatty Acids In unsaturated fatty acids, molecules cannot fit closely together, resulting in lower melting points.

Melting Points of Some Saturated Fatty Acids

Melting Points of Some Unsaturated Fatty Acids

Learning Check stearic acid (18 carbons) saturated Assign the melting points of –17 C, 13 C, and 69 C to the correct fatty acid. Explain. stearic acid (18 carbons) saturated oleic acid (18 carbons) one double bond linoleic acid (18 carbons) two double bonds

Solution Stearic acid is saturated and would have a higher melting point than the unsaturated fatty acids. Because linoleic has two double bonds, it would have a lower mp than oleic acid, which has one double bond. stearic acid mp 69 C saturated oleic acid mp 13 C linoleic acid mp –17 C most unsaturated

Prostaglandins Prostaglandins are hormone-like substances produced in cells are also known as eicosanoids, formed from arachidonic acid, the polyunsaturated fatty acid with 20 carbon atoms differ by the substituents attached to the five-carbon ring have many functions, such as lower or raising blood pressure and stimulating contraction and relaxation of uterine smooth muscle

Prostaglandins When tissues are injured, arachidonic acid is converted to prostaglandins such as PGE and PGF that produce inflammation and pain in the area.

Prostaglandins: NSAIDs The treatment of pain, fever, and inflammation is based on inhibiting the enzymes that convert arachidonic acid to prostaglandins.

Prostaglandins: NSAIDs Nonsteroidal anti-inflammatory drugs (NSAIDs) block production of prostaglandins, decreasing pain and inflammation.

Omega-3 Fatty Acids Unsaturated fats such as those in vegetable oils and fish are recognized as more beneficial to health than saturated fats. Vegetables contain omega-6 acids, meaning the first double bond occurs at carbon 6. Examples of omega-6 acids are linoleic and arachidonic acids.

Omega-3 Fatty Acids Fish have high levels of omega-3 acids, meaning the first double bond occurs at carbon 3. Examples of omega-3 acids include linolenic, eicosapentaenoic, and docosahexaenoic acids. Cold-water fish are a source of omega-3 fatty acids.

Omega-3 and Omega-6 Fatty Acids

Chapter 15 Lipids 15.3 Waxes, Fats, and Oils Waxes are esters of long-chain alcohols and fatty acids.

Waxes Waxes are esters of saturated fatty acids and long-chain alcohols coatings that prevent loss of water by leaves of plants

Fats and Oils: Triacylglycerols Fats and oils are also called triacylglycerols esters of glycerol produced by esterification formed when the hydroxyl groups of glycerol react with the carboxyl groups of fatty acids

Triacylglycerols In a triacylglycerol, glycerol forms ester bonds with three fatty acids.

Formation of a Triacylglycerol In a triacylglycerol, three hydroxyl groups on a glycerol molecule form ester bonds with the carboxyl groups of three fatty acids.

Melting Points of Fats and Oils A fat is usually solid at room temperature is prevalent in meats, whole milk, butter, and cheese An oil is usually liquid at room temperature is prevalent in plants such as olive and safflower

Oils with Unsaturated Fatty Acids have more unsaturated fats have cis double bonds that cause “kinks” in the fatty acid chains with “kinks” in the chains do not allow the triacylglycerol molecules to pack closely have lower melting points than saturated fatty acids are liquids at room temperature

Diagram of Triacylglycerol with Unsaturated Fatty Acids Unsaturated fatty acid chains with kinks cannot pack closely.

Percent Saturated and Unsaturated Fatty Acids in Fats and Oils Vegetable oils have low melting points because they have a higher percentage of unsaturated fatty acids than do animal fats.