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AMINES AND NEUROTRANSMITTERS

AMINES AND NEUROTRANSMITTERS. Tobacco products contain the addictive stimulant nicotine, an amine that is synthesized by tobacco plants as a defense against insect predators. amines. organic compounds that contain nitrogen atoms.

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AMINES AND NEUROTRANSMITTERS

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  1. AMINES ANDNEUROTRANSMITTERS

  2. Tobacco products contain the addictive stimulant nicotine, an amine that is synthesized by tobacco plants as a defense against insect predators.

  3. amines • organic compounds that contain nitrogen atoms. • The amine nitrogen atom can be bonded to one, two, or three alkyl groups, and many amines have a nitrogen atom in a ring. • All proteins contain amines, as do many vitamins and hormones. Many common amines, such as the caffeine in coffee and the nicotine in tobacco, are naturally occurring. • Synthetic drugs used as sedatives, antihistamines, and bronchodilators also contain the amine functional group.

  4. neurotransmitters • Physiologically active amines that are important chemical messengers in the body. • chemical messenger that transmits nerve impulses from one nerve cell to another cell.

  5. STRUCTURE AND BONDING • Amines are organic nitrogen compounds, formed by replacing one or more hydrogen atoms of ammonia (NH3) with alkyl groups. • Amines are classified as 1°, 2°, or 3° by the number of alkyl groups bonded to the nitrogen atom

  6. Like ammonia, the amine nitrogen atom has a lone pair of electrons, which is generally omitted in condensed structures. • A quaternary ammonium ions that contain a fourth alkyl group bonded to nitrogen. In this case, the nitrogen atom has no lone pair and bears a positive charge.

  7. The amine nitrogen atom can also be part of a ring to form a heterocycle. • For example, piperidine, one compound isolated from black pepper, and coniine, the poisonous principle of hemlock, both contain a nitrogen atom in a six-membered ring.

  8. SAMPLE PROBLEM 1 • Classify each amine in the following compounds as 1°, 2°, or 3°. • Putrescine is partly responsible for the foul odor of decaying fish. • MDMA is the illegal stimulant commonly called “Ecstasy.”

  9. seatwork • Classify each amine in the following compounds as 1°, 2°, or 3°.

  10. Classify each amine in piperidine and coniine as 1°, 2°, or 3°.

  11. Methamphetamine • is one of the many biologically active amines. • Because it imparts to the user a pleasurable “high,” methamphetamine is a widely abused illegal drug that has profound effects on the body and mind. • Methamphetamine, known as speed, meth, or crystal meth, is highly addictive, easy to synthesize, and has adverse effects on the heart, lungs, blood vessels, and other organs. • Prolonged use can lead to sleeplessness, seizures, hallucinations, paranoia, and serious heart disease.

  12. Effects of Methamphetamine Use

  13. PROBLEM 3 (a) What type of amine does methamphetamine contain? (b) Give the molecular shape around each indicated atom in methamphetamine.

  14. NOMENCLATURE • PRIMARY AMINES • Primary (1°) amines are named using either systematic or common names. • Systematic names can be used for any amine. To assign the systematic name, find the longest carbon chain bonded to the amine nitrogen, and change the -e ending of the parent alkane to the suffix -amine. • Then use the usual rules of nomenclature to number the chain and name the substituents. • Common names are used only for simple amines. To assign a common name, name the alkyl group bonded to the nitrogen atom and add the suffix -amine, forming a single word.

  15. NOMENCLATURE • SECONDARY AND TERTIARY AMINES • Secondary (2°) and 3° amines having identical alkyl groups are named by using the prefix di- or tri- with the name of the primary amine.

  16. Name 2° and 3° Amines with Different Alkyl Groups • Name the following 2° amine: (CH3)2CHNHCH3. Step [1] Name the longest alkyl chain (or largest ring) bonded to the N atom as the parent amine. • Since the longest carbon chain has 3 C’s, the parent name is propanamine. • Since the N atom is bonded to the middle carbon, the name becomes 2-propanamine.

  17. Name 2° and 3° Amines with Different Alkyl Groups Step [2] Name the other groups on the N atom as alkyl groups, alphabetize the names when there is more than one substituent, and precede each name with the prefix N-.

  18. SAMPLE PROBLEM 1 • Give a systematic name for each amine.

  19. PROBLEM 2 • Give the IUPAC name for each amine.

  20. AROMATIC AMINES • Aromatic amines, amines having a nitrogen atom bonded directly to a benzene ring, are named as derivatives of aniline.

  21. PROBLEM 3 • Draw a structure corresponding to each name: (a) N-methylaniline; (b) m-ethylaniline; (c) 3,5-diethylaniline; (d) N,N-diethylaniline.

  22. MISCELLANEOUS NOMENCLATURE FACTS • An NH2 group named as a substituent is called an amino group. • There are many different nitrogen heterocycles, and each ring type is named differently, depending on the number of N atoms in the ring and the ring size.

  23. MISCELLANEOUS NOMENCLATURE FACTS • The structures and names of four common nitrogen heterocycles are shown.

  24. PROBLEM 4 • Draw a structure corresponding to each name. a. 3-hexanamine b. N-methylpentylamine c. p-nitroaniline d. N-methylpiperidine f. 2-aminocyclohexanone g. 1-propylcyclohexanamine h. N-propylaniline

  25. PHYSICAL PROPERTIES • Many low molecular weight amines have very foul odors. • Trimethylamine [(CH3)3N], formed when enzymes break down certain fish proteins, has the characteristic odor of rotting fish. • Cadaverine (NH2CH2CH2CH2CH2CH2NH2) is a poisonous diamine with a putrid odor also present in rotting fish, and partly responsible for the odor of semen, urine, and bad breath.

  26. PHYSICAL PROPERTIES • Because nitrogen is much more electronegative than carbon or hydrogen, amines contain polar C N and N H bonds. • Primary (1°) and 2° amines are also capable of intermolecular hydrogen bonding, because they contain N H bonds.

  27. PHYSICAL PROPERTIES • Since nitrogen is less electronegative than oxygen, however, intermolecular hydrogen bonds between N and H are weaker than those between O and H. As a result:

  28. PHYSICAL PROPERTIES • Amines are soluble in organic solvents regardless of size. • Amines with fewer than six carbons are water soluble since they can hydrogen bond with water. • Larger amines are water insoluble since the nonpolar alkyl portion is too large to dissolve in the polar water solvent.

  29. PHYSICAL PROPERTIES • Which compound in each pair has the higher boiling point: (a) CH3CH2NHCH3 or CH3CH2OCH3; (b) (CH3)3N or CH3CH2CH2NH2?

  30. PROBLEM

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