Chapter 17: Amines And Amides - Latech.edu
Chapter 17: Amines and AmidesWe have discussed simple compounds containing the elements carbon, andhydrogen: Alkanes, alkenes, alkynes, and aromatic hydrocarbon are allcarbon-hydrogen compounds. The carbon-hydrogen-oxygen compounds wehave discussed include alcohols, phenols, ethers, aldehydes, ketones,carboxylic acids, and esters In this chapter we extend our discussion toorganic compounds that contain the element nitrogen.Two types of organic nitrogen-containing compounds are the focus ofthis chapter amines and amides. Amines are carbon-hydrogen-nitrogencompounds, and amides contain oxygen in addition to these elements.Amines and amides occur widely in living organisms. Many of these naturallyoccurring compounds are very active physiologically. In addition, numerousdrugs used for the treatment of mental illness, hay fever, hear problems,and other physical disorders are amines and amides.17.1 Bonding Characteristics of Nitrogen Atoms in Organic CompoundsNitrogen atoms forms three covalent bonds and has the following bondingcharacteristics: Nitrogen is a member of Group VA of the periodic tableNitrogen has five valence electronsNitrogen can form three covalent bonds to complete its octet ofelectrons17.2 Structure and Classification of AminesMolecules of ammonia (NH3) in which one or more alkyl, cycloalkyl, or arylgroups are attached to the nitrogen atom are called amines. Aryl amines are calledaromatic amines and the simplest aromatic amine is the aniline.Alkanaminesorganic derivatives of ammonia
Aromatic amine: an amine in which nitrogen is bonded to one or more arylgroups.Amines are also classified based on number of C atoms attached the nitrogen atom:Primary amines (1o): Nitrogen with one R groupSecondary amines (2o): Nitrogen with two R groupsTertiary amines (3o): Nitrogen with three R groupsQuaternary amines (4 ): Ions in which nitrogen is bonded to fourcarbons and bears a positive charge. Called tetraalkylammoniumhalidesCH3CH 3 - NH 2CH 3 - NCH3Methylamine(a 1 amine)CH 3Br CH3 - N- CH3CH 3Trimethylamine Tetramethylammonium(a 3 amine)bromide(a 4 ammonium salt)Answers:a. Primary b. Secondary c. Primary d. TertiaryCyclic amines are either secondary or tertiary amines which are designated asheterocyclic compounds. Numerous heterocyclic amines are found in biochemicalsystemsheterocyclic amine are amine in which nitrogen is one of the atoms of a ring.Examples
NNHHPiperidine Pyrrolidine(heterocyclicaliphatic amines)NNHPyrrole Pyridine(heterocyclicaromatic amines)17.3 Nomenclature for AminesAtomic groupingSuffix-aminePrefixaminoPosition in chain anywhereGeneral formula CnH2n 3NRule 1: Select as the parent carbon chain the longest chain to which thenitrogen atom is attached.Rule 2: Name the parent chain by changing the -e ending of thecorresponding alkane name to -amine.Rule 3: Number the parent chain from the end nearest the nitrogen atom.Rule 4: The position of attachment of the nitrogen atom is indicated by anumber in front of the parent chain name.Rule 5: The identity and location of any substituents are appended to thefront of the parent chain name.Examples: Primary AminesIUPAC ineethane-1,2-diamine *Structure
cyclopentanamine* Because the suffix here is -diamine which starts with a consonant, theterminal -e of the alkane name is retained.Examples : Secondary AminesThe longest chain of carbons takes the root name (alkanamine) and theother chain becomes a substituent with the locant N(italicised). The N is considered to be a lower locant than numerical locants,and so is placed ahead of them.IUPAC ineExamples : Tertiary AminesThe longest chain of carbons takes the root name (alkanamine) and theother chains become a substituents with the locant N (italicised). The N isconsidered to be a lower locant than numerical locants, and so is placedahead of them.IUPAC hylethanamine
N-ethyl-N-methylheptan-4-amine* Because the suffix here is -diamine which starts with a consonant, theterminal -e of the alkane name is retained.Naming aromatic amines17.4 Isomerism for AminesConstitutional isomerism in amines can arise from several causes. Differentcarbon atom arrangements produce isomers and Different positioning of thenitrogen atom on a carbon chain is another cause for isomerism.In secondary and tertiary amines, different partitioning of carbon atoms among thecarbon chains present produces constitutional isomers.Constitutional isomers of 1-pentamine There are three C4 secondary aminesCarbon atom partitioning can be two ethyl groups, a propyl group anda methyl group, or an isopropyl group and a methyl group.17.5 Physical Properties of AminesAmines are polar compounds, and both 1 and 2 amines form intermolecularhydrogen bonds N-H- - - -N hydrogen bonds are weaker than O-H- - - -O hydrogenbonds because the difference in electronegativity between N and H(3.0 - 2.1 0.9) is less than that between O and H (3.5 - 2.1 1.4)
CH3 CH3molecu lar w eight (g/mol)boiling point ( C)30.1-88.6CH3 NH231.1-6.3CH3 OH32.065.0Solubility in waterAmines with fewer than six carbon atoms are infinitely soluble in water.Solubility results from hydrogen bonding between the amines and water.Even tertiary amines are water-soluble because of its ability to formhydrogen bonds.Odor or smellMethylamines (mono-, di-, and tri-) and ethylamine (gases) have ammonialike smell. Most other amines are liquids and have odors resembling that ofraw fish (strong, disagreeable odors). Foul smell from dead fish and decayingflesh is due to diamines released by the bacterial decomposition of protein.Examples: putrescine and cadaverine.17.6 Basicity of Amines
Amines behave like NH3 and are basic: This behavior is due to theacceptance of H (proton)an acid.fromIn the example above water is acts as an acidThe resulting solution is alkaline due to OH- ion and a substituted ammoniumion. Ammonium and substituted ammonium ions form four bonds with N ;therefore carries a charge Names of substituted ammonium ions are derived from the parentamine in which the ―-e‖ of parent amine is replaced by ―ammoniumion‖.it is also common to discuss the basicity of amines by reference to the acidionization equilibrium constant, pKa of the corresponding conjugate acid(CH3NH3 ) and its hydrolysis given in the equation below:CH 3 NH3Ka H2 O[ CH3 NH2 ] [ H3 O ][ CH3 NH3 ]CH3 NH 2 H3 O 2.29 x 10-1 1pK a 10.64pKb value of the amine is calculated by the equation pKb 14 –pKaSmaller the pKb value more basic the amine.aliphatic amines have about the same base strength, pKb 3.0 - 4.0, and are slightlystronger bases than ammonia
17.7 Amine SaltsNames of amines salts are written in the following order: Substituted amine followed by the name of anionPutting vinegar (acid) on fish to remove odor Results in the formation of an odorless amine saltsAll amine slats are water soluble This is why drugs of amines are administered in the form of amine salts17.8 Preparation of Amines and Quaternary Ammonium SaltsPreparation of amines
a) Reaction of ammonia with alkyl halidesb) Reduction of amidesONH 2Octanam ide1 . LiAlH42 . H2 ONH 21-Octanam ineONMe 21 . LiAlH 42 . H2 ON,N -D im ethy lben zamideNMe 2N ,N-D imeth ylb enzylam inec) Reduction of Nitro Groups
Reactions of amines All amines, whether soluble or insoluble in water, react quantitativelywith strong acids to form water-soluble salts17.9 Heterocyclic AminesA heterocyclic amine is an organic compound in which nitrogen atoms ofamine groups are part of either an aromatic or a nonaromatic ring system.These compounds are the "parent" compounds for numerous derivatives thatare important in medicinal, agricultural, food, and industrial chemistry, aswell as in the functioning of the human body.Study of the heterocyclic amine structures shows that1) ring systems may be saturated, unsaturated, or aromatic,2) more than one nitrogen atom may be present in a given ring, and3) fused ring systems often occur.The two most widely used central nervous system stimulants in our society,caffeine and nicotine, are heterocyclic amine derivatives. Caffeine's structureis based on a purine ring, system. Nicotine's structure contains one pvridinering, and one pyrrolidine ring.17.10 Selected Biochemically Important AminesNeurotransmitterA neurotransmitter is a chemical substance that is released at the end of anerve, tray els across the synaptic gap between the nerve and anothernerve, and then bonds to receptor site on the other nerve, triggering a nerveimpulse. Figure 17.9 shows schemati cally how neurotransmitters function.The most important neurotransmitters in the human body are acetylcholine.Acetylcholine
The medically important mines and amides: amphetamines,barbiturates, analgesics, anesthetics, decongestants, and antibiotics.a) AmphetaminesAmphetamines are stimulants or "uppers" which are usually madesynthetically in unsafe illegal labs. The effects -- stimulation of the centralnervous system; a sense of well-being and high energy; a release of socialinhibitions; and feelings of cleverness, competence, and power -- are similarto the effects of cocaine but last longer, from 4 to 6 hours depending ondose and potency.The term "amphetamine" is used to refer to a large class of stimulants:amphetamines (black beauties, white bennies), dextroamphetamines(dexies, beans), and methamphetamines (crank, meth, crystal, speed). Thedifferent types of amphetamines have such similar chemical make-ups and
effects that even experienced users may not be able to tell which drug theyhave taken.Amphetamines can be taken orally, injected, smoked, or snorted. Injectingor smoking leads to an immediate intense sensation -- a "rush" -- that lastsonly a few minutes and is described as extremely pleasurable. Oral orintranasal use produces a milder euphoria, a high, but not a rush.Amphetamines taste extremely bitter, and injection and snorting are painful."Ice," a slang term for smokeable methamphetamine with a translucentrock-like appearance, is a highly addictive and toxic form of amphetamine.Chronic amphetamine use produces a psychosis that resemblesschizophrenia and is characterized by paranoia, picking at the skin, andauditory and visual hallucinations. Extremely violent and erratic behavior isfrequently seen among chronic abusers of amphetamines.2)BarbituratesOf all the drugs that one may become dependent on, barbiturates are one ofthe most dangerous because of the simple fact of death by overdose. On thestreet these drugs are referred to as "reds," "yellowjackets," "rainbows,""downers," "pinks" and "blockbusters." Barbiturates are usually taken orally.Their effect may be felt within 20 minutes. Barbiturates are used medicallyto relieve anxiety, tension, insomnia, epilepsy and hypertension. Peopleusing barbiturates should be aware of the extreme danger they are in if theycombine alcohol and barbiturates.The barbiturate and alcohol combination has proven to be deadly manytimes in the past. Barbiturate users run a very high risk of becomingdependent. Tolerance will build up rapidly and as larger dosages are requiredthe possibility of overdose and severe withdrawal when the user tries tostop. If the user has been taking barbiturates over an extended period oftime, a physician should assist in the withdrawal procedure. Most overdoseswith barbiturates are unintentional--barbiturate users who are withdrawingshould seek medical help.17.11 AlkaloidsAlkaloid is a nitrogen-containing organic compound extracted from plantmaterial. It is well known for centuries that physiological effects can beobtained by eating or chewing the leaves, roots, or bark of certain plants.Thousands of different compounds that are physiologically active have been
isolated from such plants. Nearly all these compounds, which are collectivelycalled alkaloids, contain amine functional groups.Three well-known compounds that we have considered previously arealkaloids. They a nicotine (tobacco plant), caffeine (coffee beans and tealeaves), and cocaine (coca plant).A number of alkaloids are currently used in medicine. Quinine, which occurscinchona bark, is used to treat malaria. Atropine, which is isolated from thebelladonna plant, is used to dilate the pupil of the eye in patients undergoingeye examination. Atropine is also used as a preoperative drug to relaxmuscles and redo the secretion of saliva in surgical patients.17.12 Structure of and Classification of AmidesThe functional group of an amide is an acyl group bonded to a trivalent nitrogen.OCH3 CNH 2A cetam ide(a 1 am ide)O HCH3 C- NCH3O CH3H- C-NCH3N- Methy lacetam ideN ,N-D im ethy l(a 2 amid e)f orm amid e (DMF)(a 3 am ide)They are derivatives of carboxylic acids in which the ―-OH‖ group of the carboxylicacid is replaced by an NH2 or NHR or NR2The basis for an amide is the -CONH2 group - known as an amide or acidamide because it is derived from a carboxylic acid.Same rules are that apply to amines to determine if they are primary, secondary ortertiary amines also apply to amides.Amide groups are considered as -R groupsAmides are also considered as derivatives of carboxylic acids (similar to esters)17.13 Nomenclature for AmidesRules for naming amides:
The ending of the name of the carboxylic acid is changed from ―-ic‖acid (common) or ―-oic‖ acid (IUPAC) to -amideExample: benzoic acid becomes benzamideThe names of groups attached to the nitrogen (2º and 3º amides) areappended to the front of the base name, using an N- prefix as alocatorto name an amide: Find the longest chain containing the carbonyl parent chainGive lowest number to Carbonyl carbonName substituents on nitrogen as N-alkylEnd name as -amideThe number of carbon atoms present determines the prefix for thecompound 1 carbon atom - methan 2 carbon atoms - ethan 3 carbon atoms - propan etc.The suffix for all amides is simply " amide" tagged onto the end of theprefix directly.Exmaple:ethanamidebutanamideIf any substituent alkyl groups are attached to the N atom in the palce og H,their presence is indicated by N-methyl for one methyl or N,N-dimethyl fortwo methyl groups. Exmaple:N-methylethanamide N,N-dimethylbutanamideClassification of amidePrimary amides (1o): Two hydrogen atoms are bonded to the amide nitrogenatomSecondary amides (2o): An alkyl (or aryl) group and a hydrogen atom arebonded to the amide nitrogen atom
Tertiary amides (3o): Two alkyl (or aryl) groups and no hydrogen atoms arebonded to the amide nitrogen atomCyclic amidesLactam: a cyclic amide name the parent carboxylic acid, drop the suffix -ic acid and add -lactam the location of the nitrogen atom in the ring is commonly indicated by aGreek letter, a, b, etc. 6-hexanolactam is an intermediate in the synthesis of nylon 6The ring size in a lactam is indicated using a Greek letter. A lactam with a fourmembered ring : Beta-lactam Beta-carbon from the carbonyl group is bonded to the heteroatom.A lactam with a five-membered ring : Gamma-lactam.The members of the penicillin family of antibiotics have four-membered lactamring.the penicillins differin the group bondedto the acyl carbonHCH2 COH HNSOPenicillin GNCH3CH3COOHThe penicillins are a family of b-lactam antibiotics one of the first discovered was penicillin G.17.14 Selected Amides and Their UsesThe cephalosporins are also b-lactam antibioticsOThe cep halosporinsdiffer in th e grou pbonded to th e carbonylcarbon.NH2H HNHONS.and th e group b on dedto th is carbon of thesix-memb ered rin gCH3COOHKeflex(a -lactam antibiotic)17.15 Physical Properties of AmidesAmides do not exhibit basic properties in solution like amines because: Electrons not available for hydrogen bonding Electrons are pulled by more electronegative atom in the carbonylgroup.17.16 Preparation of Amides
Preparation of amidesa) Carboxylic acid react with ammoniaA primary or a secondary amine produces an amide at elevated temperature A primary amine produces a secondary amide A Secondary amine produces a tertiary amideAci d partAmi ne partOR C OH RNH2ROC NH H2ORb) Acid halides react with ammonia, 1 amines, and 2 amines to formamides 2 moles of the amine are required per mole of acid chloride; one toform the amide and one to neutralize the HCl formed.OOCl 2 NH3Hexan oylA mmoniach lorideNH2Hexan amid e -NH4 ClAmmoniumchloridec) Acid anhydrides react with ammonia, and with 1 and 2 amines to formamides2 moles of ammonia or amine are required; one to form the amide and one toneutralize the carboxylic acid byproducthere the reaction is broken into two stepsO O NH3CH 3 COCCH3OCH3 COH NH3O OCH 3 COCCH3 2 NH3OOCH 3 CNH2 CH3 COHOCH 3 CO- NH 4 OOCH3 CNH2 CH3 CO- NH4 d) Esters react with ammonia, and with 1 and 2 amines to form amidesesters are less reactive than either acid halides or acid anhydridesOPhOOEthyl phenylacetate N H3PhN H2Phenyl acetamideAmides do not react with ammonia, or with 1 or 2 aminesPreparation of amides: Summary HOEthanol
OR-C-Cl 2 NH3OR-C-NH2 NH4 Cl-OOR-C-O-C-R 2 NH3OO R-C-NH2 R-C-O NH4OR-C-OR' NH3OR-C-NH2 R'OHOR-C-NH2 N o reaction w ith ammonia or amines17.17 Hydrolysis of AmidesHydrolysis of an amide requires much more vigorous conditions than hydrolysis ofan ester hydrolysis in aqueous acid requires 1 mole of acid for each mole of amide the products are a carboxylic acid and an ammonium or an amine saltOOH2 O OH NH4 ClNH2 H2 O HClheatPhPh2-Phenylbutan amide2-Phen ylb utanoic acidhydrolysis of an amide in aqueous base requires 1 mole of base per mole of amidethe products are a carboxylate salt and an amineOCH3 CNH NaOHH2 ide)O CH3 CO Na H2 NSodiu m acetateAniline17.18 Polyamides and PolyurethanesAmide polymers or polyamides: Synthesized by combining diamines anddicarboxylic acids in a condensation polymerization reaction similar topolyester formation.Nylon is a synthetic polyamideMany different types of Nylons Based on diamine and diacid monomers usedNylon 66 – a polymer of hexanedioic acid and 1,6-hexanediamine asmonomers shown below:
Urethane: A hydrocarbon derivative containing a carbonyl group bonded toboth an —OR group and a —NHR (or –NR2) group.Polyurethane: A polymer formed from the reaction of dialcohol anddiisocyanate monomers.Properties of polyamidesAdditional stiffness and toughness are imparted to polyamides with theintroduction of aromatic rings to the polymer ―backbone.‖Polyamide Kevlar is one such polymer and it is used in making bulletresistant vests.Silk and wool are examples of naturally occurring polyamide polymers.Much of the human body is also polyamide polymer.The structure of the amide bond and peptide bonds in peptides.Amides are most usually formed by the reaction of an acid chloride ( R-COCl
) with ammonia ( NH3 ) or a primary amine ( R'-NH2 ). The combination ofan amine and an acid produces an amide (containing a N-C O) and thepolyfunctional compounds amino acids with contain –NH2 and –COOHgroups on the a-carbon atoms polymerize to form peptides.Polypeptide containing four amino acids monomers:N-nitrosamines are carcinogens
Naming aromatic amines 17.4 Isomerism for Amines Constitutional isomerism in amines can arise from several causes. Different carbon atom arrangements produce isomers and Different positioning of the nitrogen atom on a carbon chain is another cause for isomerism. In secondary and tertiary amines, different partitioning of carbon atoms among the
Chemistry B11 Bakersfield College Chemistry B11 Chapters 14 Amines, aldehydes, ketones and carboxylic acids Amines: are derivatives from ammonia (NH3). Aliphatic amines: an amine in which nitrogen is bonded only to alkyl group or hydrogens. Aromatic amines: an amine in which nitrogen is bonded to one or more aromatic rings. Note: amines are classified as primary ( 1), secondary .
We have already seen the reaction of various amines with ketones and aldehydes to generate imines and their analogues. E.g. Ch19 Amines(landscape).docx Page 21 Aromatic Substitution of Aryl and Heterocyclic Amines Aryl amines are activating, ortho/para directors in electrophilic aromatic substitution reactions, since the lone pair
Part One: Heir of Ash Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26 Chapter 27 Chapter 28 Chapter 29 Chapter 30 .
nucleic acids, alkaloid drugs, etc. (Alkaloids are N-containing, weakly basic organic compounds; thousands of these substances are known.) Amines are organic derivatives of ammonia, NH3, in which one or more of the three H’s is replaced by a carbon group. Amines are classified as primary (1 ), secondary
Feb 08, 2016 · ABSTRACT This is a review of the safety of 20 alkyl taurate amides and taurate salts as used in cosmetics. The alkyl taurate amides and taurate salts in this report are all structurally related by
Alkene Metathesis Reactions: What are Effective Initiators for the Process? Acids A lcohols, Water Ald ehydes Ke tones Esters, Amides Olefins Acids lcohs,Water Al ehys Ktons Olefins Esters, Amides Acids Alcohols, Water Aldehydes Olefins Ketones Esters, Amides Functional group reactivity Mo N
TO KILL A MOCKINGBIRD. Contents Dedication Epigraph Part One Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Part Two Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18. Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26
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