Amines

10 Key excerpts on "Amines"

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  eBook - PDF

  Introduction to General, Organic, and Biochemistry

  • Morris Hein, Scott Pattison, Susan Arena, Leo R. Best(Authors)
  • 2014(Publication Date)
  • Wiley

    (Publisher)

  An amine (pronounced ameen) is a substituted ammonia molecule with basic properties and has the general formula RNH 2 , R 2 NH, or R 3 N, where R is an alkyl or an aryl group. Amines are classified as primary (1°), secondary (2°), or tertiary (3°), depending on the number of hydrocarbon groups attached to the nitrogen atom. Some examples include the following: KEY TERM urea KEY TERMS amine heterocyclic compound A Biochemical Perspective: Silk, a natural fiber, is a polyamide composed of amino acids—a protein. During World War II, ladies valued nylon stockings more than gold. The stock of early Remington 22- caliber rifles was very popular and was made of nylon. Instead of urea, uric acid is excreted by birds and reptiles. LEARNING OBJECTIVE LEARNING OBJECTIVE Crops are often fertilized with urea. Lloyd Sutton/Masterfile 25.5 • Amines: Nomenclature and Physical Properties 649 H N H H CH 3 N H H ammonia methylamine (1� amine) N CH 2 CH 3 H CH 3 ethylmethylamine (2� amine) CH 3 CH 2 N CH 2 CH 3 CH 2 CH 3 triethylamine (3 amine) NH 2 aniline (1° amine) NH 2 cyclohexylamine (1° amine) More Practice? Try Paired Exercises 13–16. P R A C T I C E 2 5 . 4 Identify these compounds as 1°, 2°, or 3° Amines: (a) CH 3 CH 2 CH 2 NH 2 (e) CH 3 CH 2 NCH 2 CH 3 CH 3 (b) NH 2 CH 3 C CH 3 CH 3 (f) CH 3 CH 2 NHCH 2 CH 3 (c) N H (g) CH 2 NH 2 (d) NH 2 P R A C T I C E 2 5 . 5 Application to Biochemistry The following Amines are synthesized by humans: (a) N H CH 2 ¬ CH 2 ¬ NH 2 ¬ (b) CH ¬ CH 2 ¬ NH ¬ CH 3 OH OH HO ¬ “ CH 3 NH 2 ¬ CH ¬ (c) tryptamine epinephrine (adrenaline) alanine C OH O Identify each amine functional group as 1°, 2°, or 3°. Health Connection: Some tertiary Amines put a stop to pain The history of local anesthetics traces a path taken in many drug discoveries, that is, starting with a natural molecule that has a desired physiological impact and making it better using organic chemistry. Surprisingly, cocaine, a much-abused narcotic, is also a very good local anesthetic.

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  Organic Chemistry

  • David R. Klein(Author)
  • 2021(Publication Date)
  • Wiley

    (Publisher)

  22.1 Introduction to Amines 1055 DO YOU REMEMBER? Before you go on, be sure you understand the following topics. If necessary, review the suggested sections to prepare for this chapter: • Delocalized and Localized Lone Pairs (Section 2.13) • Brønsted–Lowry Acidity: A Quantitative Perspective (Section 3.3) • Aromatic Heterocycles (Section 17.5) • Activating Groups and Deactivating Groups (Sections 18.7 and 18.8) Take the DO YOU REMEMBER? QUIZ in the online course to check your understanding. 22.1 Introduction to Amines Classification of Amines Amines are derivatives of ammonia in which one or more of the protons have been replaced with alkyl or aryl groups. Amines Ammonia H N H H Primary (1°) H N R H Secondary (2°) R N R H Tertiary (3°) R N R R Amines are classified as primary, secondary, or tertiary, depending on the number of groups attached to the nitrogen atom. Note that these terms have a different meaning than when they were used in naming alcohols. A tertiary alcohol has three groups attached to the α carbon, while a tertiary amine has three groups attached to the nitrogen atom. Amines are abundant in nature. Naturally occurring Amines isolated from plants are called alkaloids. Below are examples of several alkaloids that have garnered public awareness as a result of their physiological activity: O OH OH H N Morphine (A potent analgesic isolated from the unripe seeds of the poppy plant Papaver somniferum) N O O O O Cocaine (A potent stimulant isolated from the leaves of the coca plant) Nicotine (An addictive and toxic compound found in tobacco) N N Many Amines also play vital roles in neurochemistry (chemistry taking place in the brain).

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  Chemistry for Today

  General, Organic, and Biochemistry

  • Spencer Seager, Michael Slabaugh, Maren Hansen, , Spencer Seager, Spencer Seager, Michael Slabaugh, Maren Hansen(Authors)
  • 2021(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  16.1 Classification of Amines Learning Objective 1 Classify Amines as primary, secondary, or tertiary on the basis of given structural formulas. Amines are organic derivatives of ammonia, NH 3 , in which one or more of the hydrogens are replaced by an aromatic or alkyl group (R). Like alcohols, Amines are classified as primary, secondary, or tertiary on the basis of molecular structure. However, the classification is done differently. When classifying Amines, the number of groups (R) that have replaced hydrogens in the NH 3 is counted. The nitrogen atom in a primary amine is bonded to one R group. The nitrogen in secondary Amines is bonded to two R groups, and that of tertiary Amines is bonded to three R groups. These amine subclasses are summarized in Table 16.1. amine An organic compound derived by replacing one or more of the hydrogen atoms of ammonia with alkyl or aromatic groups, as in RNH 2 , R 2 NH, and R 3 N. primary amine An amine having one alkyl or aromatic group bonded to nitrogen, as in R—NH 2 . secondary amine An amine having two alkyl or aromatic groups bonded to nitrogen, as in R 2 NH. tertiary amine An amine having three alkyl or aromatic groups bonded to nitrogen, as in R 3 N. TABLE 16.1 Subclasses of Amines Subclass General Formula Example Primary (1°) Secondary (2°) Tertiary (3°) N R H H N CH 3 H H N R R′ H N CH 3 CH 3 H N R R′ R″ N CH 3 CH 3 CH 3 Example 16.1 Classifying Amines Serotonin, an amine involved in the transmission of nerve impulses, contains two nitro- gen atoms in its structure. Classify each of the following nitrogens as primary, second- ary, or tertiary. NH 2 H N CH 2 CH 2 Copyright 2022 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience.

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  eBook - ePub

  Organic Chemistry Study Guide

  Key Concepts, Problems, and Solutions

  • Robert J. Ouellette, J. David Rawn(Authors)
  • 2014(Publication Date)
  • Elsevier

    (Publisher)

  Amines are classified according to the number of alkyl or aryl groups bonded to the nitrogen atom. Primary, secondary, and tertiary Amines have 1, 2, and 3 groups bonded, respectively. Amides are classified the same way, with the acyl group counting as one of the carbon groups bonded to the nitrogen atom. Abbreviations for the classes of Amines and amides are 1°, 2°, and 3°.

  The common names of simple Amines are based on the identity of the alkyl or aryl groups bonded to the nitrogen atom. The names of the alkyl groups are written in alphabetical sequence as one word, followed by the word amine.

  The common name of a complex amine is based first on identifying the longest continuous chain containing an attached nitrogen atom. The chain is numbered to assign the lowest number to the carbon atom bonded to the nitrogen atom. The nitrogen atom may be contained in an amino group (—NH2 ), an N -alkylamino group (—NHR), or an N ,N -dialkylamino group (—NR2 ). Aryl groups may be present in place of alkyl groups, and the same procedure is followed. In naming alkylamino or arylamino groups, the prefix N -indicates that the alkyl or aryl group is attached to the nitrogen atom, and not to the parent chain.

  The IUPAC name of an amine is also based on the longest continuous chain containing an attached nitrogen atom. The -e ending of the parent alkane is changed to -amine. The chain is numbered to give the lowest number to the carbon atom bearing the nitrogen atom. Alkyl groups attached to nitrogen are designated with N -, but they are named along with other substituents on the parent chain.

  Heterocyclic aromatic Amines have rings that are numbered using a selected nitrogen atom as the number one atom. The Chemical Abstract System (CAS) of heterocyclic ring nomenclature has been accepted by the IUPAC. We use CAS names in this text.

  23.4 Physical Properties of Amines

  Amines may be gases, liquids, or solids depending on their molecular weight and structure. The boiling points of primary and secondary Amines are higher than those for alkanes of similar molecular weight because these Amines form intermolecular hydrogen bonds. Tertiary Amines have lower boiling points than isomeric primary and secondary Amines because tertiary Amines do not have an N—H bond to form intermolecular hydrogen bonds. The lower molecular weight Amines are soluble in water as a result of hydrogen bonding to water molecules.

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  Klein's Organic Chemistry

  • David R. Klein(Author)
  • 2020(Publication Date)
  • Wiley

    (Publisher)

  Amines 23.1 Introduction to Amines 23.2 Nomenclature of Amines 23.3 Properties of Amines 23.4 Preparation of Amines: A Review 23.5 Preparation of Amines via Substitution Reactions 23.6 Preparation of Amines via Reductive Amination 23.7 Synthesis Strategies 23.8 Acylation of Amines 23.9 Hofmann Elimination 23.10 Reactions of Amines with Nitrous Acid 23.11 Reactions of Aryl Diazonium Ions 23.12 Nitrogen Heterocycles 23.13 Spectroscopy of Amines 23 DID YOU EVER WONDER . . . how drugs like Tagamet, Zantac, and Pepcid are able to control stomach acid production and alleviate the symptoms of acid reflux disease? T agamet, Zantac, and Pepcid are all compounds that contain several nitrogen atoms, which are important for the function of these drugs. In this chapter, we will explore the properties, reactions, and biological activity of many different nitrogen-containing compounds. The end of the chapter will revisit the structures and activity of the three drugs listed above, with a special emphasis on how medicinal chemists designed the first of these blockbuster drugs. 23.1 Introduction to Amines 1053 23.1 INTRODUCTION TO Amines Classification of Amines Amines are derivatives of ammonia in which one or more of the protons have been replaced with alkyl or aryl groups. Amines Ammonia H N H H Primary (1°) H N R H Secondary (2°) R N R H Tertiary (3°) R N R R Amines are classified as primary, secondary, or tertiary, depending on the number of groups attached to the nitrogen atom. Note that these terms have a different meaning than when they were used in naming alcohols. A tertiary alcohol has three groups attached to the α carbon, while a tertiary amine has three groups attached to the nitrogen atom. Amines are abundant in nature. Naturally occurring Amines isolated from plants are called alkaloids.

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  eBook - ePub

  Principles of Organic Chemistry

  • Robert J. Ouellette, J. David Rawn(Authors)
  • 2015(Publication Date)
  • Elsevier

    (Publisher)

  12

  Amines and Amides

  12.1 Organic Nitrogen Compounds

  For most of this text we have concentrated on the compounds of carbon, hydrogen, and oxygen. We have paid less attention to compounds containing sulfur and nitrogen. Nitrogen is the fourth most common element in living systems after carbon, hydrogen, and oxygen. Organic compounds containing nitrogen are widely distributed in plants and animals and are necessary for life. Nitrogen is present in many vitamins and hormones. Nitrogen is essential in amino acids and proteins, in nucleotides and nucleic acids, and in scores of other cellular molecules. In addition, many nitrogen-containing compounds are important industrial products, including polymers such as nylon, many dyes, explosives, and pharmaceutical agents.

  A nitrogen atom, which has five valence electrons, forms a total of three covalent bonds to carbon or hydrogen atoms in neutral compounds. A nitrogen atom in a functional group can form single, double, or triple bonds. We have discussed these functional groups in previous chapters. In this chapter we will focus on Amines and amides, but we will also discuss other functional groups that are either the reactants required to form Amines and amides or the products of their reactions.

  Some Amines affect the brain, spinal cord, and nervous system. These compounds include the neurotransmitters epinephrine, serotonin, and dopamine (Figure 12.1 ). Epinephrine, commonly called adrenaline, stimulates the conversion of stored glycogen into glucose. Serotonin is a hormone that causes sleep, and serotonin deficiency is responsible for some forms of mental depression. In Parkinson's disease, the dopamine concentration is low.

  Figure 12.1 Structures of Neurotransmitters

  Proteins are made from nitrogen-containing molecules called α-amino acids. In proteins, each amine functional group of one α-amino acid is bonded to the carbonyl carbon of another α-amino acid in a chain of amino acyl groups that contains many amide bonds, or peptide bonds.

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  eBook - PDF

  Organic Chemistry

  • David R. Klein(Author)
  • 2016(Publication Date)
  • Wiley

    (Publisher)

  Note that these terms have a different meaning than when they were used in naming alcohols. A tertiary alcohol has three groups attached to the α carbon, while a tertiary amine has three groups attached to the nitrogen atom. Amines are abundant in nature. Naturally occurring Amines isolated from plants are called alkaloids. Below are examples of several alkaloids that have garnered public awareness as a result of their physiological activity: O OH OH H N Morphine (A potent analgesic isolated from the unripe seeds of the poppy plant Papaver somniferum) N O O O O Cocaine (A potent stimulant isolated from the leaves of the coca plant) Nicotine (An addictive and toxic compound found in tobacco) N N Many Amines also play vital roles in neurochemistry (chemistry taking place in the brain). Below are a few examples: Dopamine (Regulates motor skills and emotions) HO HO N H H Adrenaline (A “fight-or-flight” hormone, first discussed in Chapter 7) HO HO N CH 3 H OH Noradrenaline (Regulates heart rate and dilates air passages) HO HO N H H OH In fact, many pharmaceuticals are Amines, as we will see throughout this chapter. DO YOU REMEMBER? Before you go on, be sure you understand the following topics. If necessary, review the suggested sections to prepare for this chapter: • Delocalized and Localized Lone Pairs (Section 2.12) • Brønsted–Lowry Acidity: A Quantitative Perspective (Section 3.3) • Aromatic Heterocycles (Section 17.5) • Activating Groups and Deactivating Groups (Sections 18.7 and 18.8) Take the DO YOU REMEMBER? QUIZ in to check your understanding. 1010 CHAPTER 22 Amines Reactivity of Amines The nitrogen atom of an amine possesses a lone pair that represents a region of high electron density. This can be seen in an electrostatic potential map of trimethylamine (Figure 22.1). The presence of this lone pair is responsible for most of the reactions exhibited by Amines.

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  eBook - ePub

  Organic Chemistry, Volume One

  Part I: Aliphatic Compounds Part II: Alicyclic Compounds

  • Frank C. Whitmore(Author)
  • 2012(Publication Date)
  • Dover Publications

    (Publisher)

  VIII. Amines, ALKYL DERIVATIVES OF AMMONIA

  Depending on the number of H atoms replaced in NH3 , the Amines are primary, secondary and tertiary, RNH2 (amino group, −NH2 ), RR´NH (imino group, =NH), and RR′R′′N respectively. They have the basic properties of ammonia but form more strongly basic solutions probably because of the greater stability of their “hydrates” as compared with that of ammonia. The primary and secondary Amines are “alcohols of the ammonia system”730 , while the tertiary Amines are “ethers” on the same basis. The lower Amines have characteristic odors somewhat resembling that of NH3 . The three methylAmines and primary ethylamine boil below 20°. The others are liquids with boiling points increasing with their molecular weights to heptadecylamine at 340° and tri-n -octylamine at 366°. Branching lowers the boiling points as in the alcohols. This is shown by the following isomeric (metameric) Amines: Et3 N, 90°; Pr2 NH, 110°; HexNH2 , 129°. The densities of the Amines range from 0.66 to 0.77.

  The preparations and reactions of the Amines can be more safely generalized than can those of the alcohols. There are few reactions of Amines in which the C−N linkage is broken whereas most reactions of alcohols involve the breaking of the C−O linkage. The outstanding example of the breaking of a C−N linkage, the action of nitrous acid with a primary amine, presents even more irregularities than any alcohol reaction (p. 172).

  The Amines unite with HX in the same way that NH3 does, forming salts such as NH4 Cl, RNH3 Cl, R2 NH2 Cl, R3 NHCl, etc. The substituted ammonium salts (amine hydrochlorides etc.) have much the same properties as the parent substance. They are very soluble crystalline compounds. They are more soluble in organic liquids than the simple ammonium salts. Ammonia and the Amines add certain alkyl halides to give ammonium salts having one more alkyl group than the starting material. The last possible stage is a quaternary ammonium compound R4 NX. The corresponding hydroxides RNH3 OH, R2 NH2 OH, R3 NHOH, R4 NOH, act as stronger bases than the parent ammonium hydroxide probably because of their greater stability. Me4 NOH can be obtained as a solid resembling KOH in physical and chemical properties. On heating, however, it decomposes giving Me3 N and MeOH. Secondary Amines give stronger bases than either the corresponding primary or tertiary Amines.731

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  eBook - ePub

  Pharmaceutical Chemistry E-Book

  • David G. Watson(Author)
  • 2011(Publication Date)
  • Churchill Livingstone

    (Publisher)

  Chapter 3 Amines David G. Watson Chapter contents Introduction 35 Factors affecting the p Ka value of a base 36 Alkyl groups 36 Electron withdrawing groups 39 Salt formation 48 Reactions of Amines in relation to storage and formulation 48 Oxidation 48 Acylation 48 Schiff’s base formation 49 Quaternary Amines 52 Introduction The amine group can be considered as the single most important group for conferring pharmacological activity. This is because it is the principle group within organic molecules that bears a positive charge. When it is present in a drug molecule it can exert biological effects through electrostatic interactions with negatively charged groups within proteins and also compete with positively charged cations such as sodium, potassium and calcium ions in biological processes. Amines are derived from ammonia and have the structures shown in Figure 3.1 for mono-, di- and trisubstituted nitrogen. Figure 3.1 Amines. The structures may look planar but, in fact, the structures of Amines are more or less tetrahedral, like tetrasubstituted carbon, as shown for trimethylamine in Figure 3.2. In the case of nitrogen, the position that would be occupied by a fourth bond in tetrasubstituted carbon is occupied by a lone pair of electrons. Since nitrogen is less electronegative than oxygen the lone pair within an amine structure is more available than the lone pairs on an oxygen atom to interact with a proton. An approximate measure of the availability of lone pairs of electrons is given by the energy of the highest occupied molecular orbital (HOMO). The deeper the ‘energy well’ that the molecular orbital occupies the less available the electrons are for bond formation with a proton. Thus water has a HOMO of −12.5 eV while ammonia has a HOMO of −10.5 eV, and thus its electrons are more available and it protonates more readily than water

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  Organic and Biological Chemistry

  • H. Stephen Stoker(Author)
  • 2015(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 218 CHAPTER 6 Amines and Amides 6-10 Selected Biochemically Important Amines L E A R N I N G F O C U S Be familiar with common heterocyclic Amines that have the following functions in the human body: (1) neurotransmitter, (2) central nervous system stimulant, and (3) decongestant. Amines that contain no other functional groups than the amino group are often toxic substances and generally are not prevalent in biological systems. On the other hand, many Amines that contain additional functional groups besides the amino group are physiologically active compounds that affect the functioning of the human body. Some are naturally present biosynthesized compounds, others are substances isolated from plants, and still others are laboratory-synthesized products that find use in both prescription and nonprescription drugs. In this section, Amines that exert the follow-ing types of effects are considered: (1) neurotransmitters, (2) central nervous system stimulants, and (3) decongestants. Two commonly encountered “core” structures for polyfunctional Amines with phys-iological effects are the phenethylamine core and the tryptamine core. These two core structures, both of which are encountered in compounds discussed in this section are: CH 2 CH 2 NH 2 CH 2 CH 2 NH 2 N H Phenethylamine core: Tryptamine core: These two structures differ in the ring structure present [benzene versus indole (Figure 6-8)] and are similar in that an ethylamine group is attached to the ring structure. Neurotransmitters Neurotransmitters are substances present in the human body that assist in passing nerve impulses from one cell to another.

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