Nitrogen containing compounds. Nitrocompounds. Amines. Diazo- and azocompounds.

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• Nitrogen containing compounds. Nitrocompounds.
  Amines. Diazo- and azocompounds.

Prepared by ass. Medvid I.I., ass. Burmas N.I.
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Outline

• Nitroderivates of hydrocarbons.
• The methods of extraction of nitroalkanes.
• Chemical properties of nitroalkanes.
• The aromatic nitrocompounds.
• Amines.
• Isomery of amines.
• Structure and bonding of amines.
• Physical properties of amines.
• The methods of extraction of amines.
• Chemical properties of amines.
• Synthetically useful transformations involving
  aryl diazonium ions.
• The medico-biological importance of amines.
• Aminoalcohols.
• The methods of extraction of aminoalcohols.
• Chemical properties of aminoalcohols.
• Arylamines.
• The methods of extraction of aromatic amines.
• Physical properties of aromatic amines
• Comparative structure of aromatic and aliphatic
  amines

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1. Nitroderivates of hydrocarbons

• Nitrocompounds are the derivatives of
  hydrocarbons which contain one or several groups
  NO2 in their molecule. Nitroalkanes are
  poisonous colourless or yellowish liquids with
  good smell. They are not dissoluble in water but
  are dissoluble in organic solvents. The names of
  nitrocompound are formed by adding prefix nitro-
  to the names of hydrocarbons. The isomery of
  nitrocompound is specified by different structure
  of carbon chain and different location of group
  NO2 in the molecule.

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• 2. The methods of extraction of nitroalkanes
• 1. Nitration of alkanes
• CH3-CH3 HNO3 ? CH3-CH2-NO2 H2O
• 2. The reaction of halogenalkanes with salts of
  HNO2
• CH3-CH2-I NaNO2 ? CH3-CH2-NO2 NaI
• 3. Oxidation of amines

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3.Chemical properties of nitroalkanes

• Chemical properties of nitroalkanes are specified
  by the presence of group NO2 in the structure of
  the molecule.
• Reaction with HNO2
• Reaction with aldehydes and ketones
• 3. Reduction of nitroalkanes. In the result of
  this reaction amines form (catalyst is SnCl2)
• CH3-CH2-NO2 3H2 ? CH3-CH2-NH2 2H2O

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4.The aromatic nitrocompounds

• The simplest aromatic nitro compound, having the
  molecular formula C6H5NO2.
• Nitrobenzene, also known as nitrobenzol or oil
  of mirbane, is an organic compound with the
  chemical formula C6H5NO2. Nitrobenzene is a
  water-insoluble oil which exhibits a pale yellow
  to yellow-brown coloration in liquid form (at
  room temperature and pressure) with an
  almond-like odor. When frozen, it appears as a
  greenish-yellow crystal. Although occasionally
  used as a flavoring or perfume additive,
  nitrobenzene is highly toxic in large quantities
  and is mainly produced as a precursor to aniline.
  In the laboratory, it is occasionally used as a
  solvent, especially for electrophilic reagents.

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Properties of nitrobenzene

• 1. Production
• Nitrobenzene is prepared by nitration of benzene
  with a mixture of concentrated sulfuric acid,
  water, and nitric acid, called "mixed acid." Its
  production is one of the most dangerous processes
  conducted in the chemical industry because of the
  exothermicity of the reaction (?H -117 kJ/mol).
• There were four producers of nitrobenzene in the
  United States in 1991.
• 2. Mechanism of nitration
• The reaction pathway entails formation of an
  adduct between the Lewis acidic nitronium ion,
  NO2, and benzene. The nitronium ion is generated
  in situ via the reaction of nitric acid and an
  acidic dehydration agent, typically sulfuric
  acid
• HNO3 H ? NO2 H2O

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Zinins reaction
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• 3. Uses
• Approximately 95 of nitrobenzene is consumed in
  the production of aniline.
• 4. Specialized applications
• More specialized applications include the use of
  nitrobenzene as a precursor to rubber chemicals,
  pesticides, dyes, explosives, and
  pharmaceuticals. Nitrobenzene is also used in
  shoe and floor polishes, leather dressings, paint
  solvents, and other materials to mask unpleasant
  odors. Redistilled, as oil of mirbane,
  nitrobenzene has been used as an inexpensive
  perfume for soaps. A significant merchant market
  for nitrobenzene is its use in the production of
  the analgesic paracetamol (also known as
  acetaminophen) (Mannsville 1991). Nitrobenzene is
  also used in Kerr cells, as it has an unusually
  large Kerr constant.

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• 5. Organic reactions
• Aside from its conversion to aniline,
  nitrobenzene is readily converted to related
  derivatives such as azobenzene, nitrosobenzene,
  and phenylhydroxylamine. The nitro- group is
  deactivating, thus substitution tends to occur at
  the meta-position.
• 6. Safety
• Nitrobenzene is highly toxic (TLV 5 mg/m3) and
  readily absorbed through the skin.
• Although nitrobenzene is not currently known to
  be a carcinogen, prolonged exposure may cause
  serious damage to the central nervous system,
  impair vision, cause liver or kidney damage,
  anemia and lung irritation. Inhalation of fumes
  may induce headache, nausea, fatigue, dizziness,
  cyanosis, weakness in the arms and legs, and in
  rare cases may be fatal. The oil is readily
  absorbed through the skin and may increase heart
  rate, cause convulsions or rarely death.
  Ingestion may similarly cause headaches,
  dizziness, nausea, vomiting and gastrointestinal
  irritation.

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5. Amines

• Amines are the derivatives of ammonium. In its
  molecules atoms of hydrogen (1,2 or 3) are
  substituted to atoms of hydrocarbon radicals.
• The names of amines are formed by adding suffix
  -amine to the names of hydrocarbon radical.

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• 6. Isomery of amines
• Isomery of amines is specified by different
  structure of hydrocarbon radicals, different
  location of aminogroup and methamery. Methamery
  is a phenomenon when amines have the same
  molecular formula but can be primary, secondary
  or tertiary.

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• Aniline is the parent IUPAC name for
  amino-substituted derivatives of benzene.
  Substituted derivatives of aniline are numbered
  beginning at the carbon that bears the amino
  group. Substituents are listed in alphabetical
  order, and the direction of numbering is governed
  by the usual first point of difference rule.
• Arylamines may also be named as arenamines.
  Thus, benzenamine is an alternative, but rarely
  used, name for aniline. Compounds with two amino
  groups are named by adding the suffix -diamine to
• the name of the corresponding alkane or arene.
  The final -e of the parent hydrocarbon is
  retained.

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• Amino groups rank rather low in seniority when
  the parent compound is identified for naming
  purposes. Hydroxyl groups and carbonyl groups
  outrank amino groups. In these cases, the amino
  group is named as a substituent.
• Secondary and tertiary amines are named as
  N-substituted derivatives of primary amines. The
  parent primary amine is taken to be the one with
  the longest carbon chain. The prefix N- is added
  as a locant to identify substituents on the amino
  nitrogen as needed.

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7. Structure and bonding of amines

• Alkylamines As shown in Figure.1 methylamine,
  like ammonia, has a pyramidal arrangement of
  bonds to nitrogen. Its H-N-H angles (106) are
  slightly smaller than
• the tetrahedral value of 109.5, whereas the
  C-N-H angle (112) is slightly larger. The C-N
  bond distance of 147 pm lies between typical C-C
  bond distances in alkanes
• (153 pm) and C-O bond distances in alcohols (143
  pm). An orbital hybridization description of
  bonding in methylamine is shown in Figure. 2.
  Nitrogen and carbon are both sp3-hybridized and
  are joined by a s bond.

Figure.1 Methylamine
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• Arylamines Aniline, like alkylamines, has a
  pyramidal arrangement of bonds around nitrogen,
  but its pyramid is somewhat shallower. One
  measure of the extent of this flattening is given
  by the angle between the carbonnitrogen bond and
  the bisector of the H-N-H angle.
• For sp3-hybridized nitrogen, this angle (not the
  same as the C-N-H bond angle) is 125, and the
  measured angles in simple alkylamines are close
  to that. The corresponding angle for sp2
  hybridization at nitrogen with a planar
  arrangement of bonds, as in amides, for example,
  is 180. The measured value for this angle in
  aniline is 142.5, suggesting a hybridization
  somewhat closer to sp3 than to sp2.

Figure.2
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• The corresponding resonance description shows
  the delocalization of the nitrogen lone-pair
  electrons in terms of contributions from dipolar
  structures.

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8.Physical properties of amines

• We have often seen that the polar nature of a
  substance can affect physical properties such as
  boiling point. This is true for amines, which are
  more polar than alkanes but less polar than
  alcohols. For similarly constituted compounds,
  alkylamines have boiling points higher than those
  of alkanes but lower than those of alcohols.
• Dipoledipole interactions, especially hydrogen
  bonding, are present in amines but absent in
  alkanes. The less polar nature of amines as
  compared with alcohols, however, makes these
  intermolecular forces weaker in amines than in
  alcohols. Among isomeric amines, primary amines
  have the highest boiling points, and tertiary
  amines the lowest.

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• Primary and secondary amines can participate in
  intermolecular hydrogen bonding, but tertiary
  amines cannot. Amines that have fewer than six or
  seven carbon atoms are soluble in water. All
  amines, even tertiary amines, can act as proton
  acceptors in hydrogen bonding to water molecules.
  The simplest arylamine, aniline, is a liquid at
  room temperature and has a boiling
• point of 184C. Almost all other arylamines have
  higher boiling points. Aniline is only slightly
  soluble in water (3 g/100 mL). Substituted
  derivatives of aniline tend to be even less
  water-soluble.

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9. The methods of extraction of amines
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• Hoffman reaction
  
  
  NH3
• NH3 CH3I ? CH3NH3I- ? CH3NH2 NH4I
  
  
  
  
  NH3
• CH3NH2 CH3I ? (CH3)2NH2I- ? (CH3)2NH
  NH4I
• 
  NH3
• (CH3)2NH CH3I ? (CH3)3NHI- ? (CH3)3N NH4I
• NH3
• (CH3)3N CH3I ? (CH3)4NI-
• Gabriele synthesis

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10. Chemical properties of amines
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Nitrosation of arylamines
We learned in the preceding section that
different reactions are observed when the various
classes of alkylaminesprimary, secondary, and
tertiaryreact with nitrosating agents.
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• Primary arylamines, like primary alkylamines,
  form diazonium ion salts on nitrosation. Aryl
  diazonium ions are considerably more stable than
  their alkyl counterparts. Whereas alkyl diazonium
  ions decompose under the conditions of their
  formation, aryl diazonium salts are stable enough
  to be stored in aqueous solution at 05C for
  reasonable periods of time. Loss of nitrogen from
  an aryl diazonium ion generates an unstable aryl
  cation and is much slower than loss of nitrogen
  from an alkyl diazonium ion.

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• Reaction with acids
• CH3CH2NH2 HCl ? CH3CH2NH3Cl-
• Reaction with halogenalkanes
• CH3CH2NH2 CH3-I ? CH3CH2NH3I- ? CH3CH2NHCH3
  HI
• Reaction with functional derivatives of
  carboxylic acids. In the result of these
  reactions amides form.
• Reaction with HNO2
• Isonitrylic reaction

Oxidation C2H5NH2 O3 ? C2H5NO2 H2O
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11. Synthetically useful transformations
involving aryl diazonium ions
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• 12.The medico-biological importance of amines
• Methylamine CH3NH2. It is a gas with the smell of
  ammonium. Methylamine is used in the production
  of medicines, dyes, insecticides and fungicides.
• Putrescin NH2CH2CH2CH2CH2NH2 (tetramethylendiamine
  ). It is crystal solid. It is formed in the
  process of rotting of corpses. In the human
  organism it is used for synthesis of biologically
  active polyamines which take part in the
  biosynthesis of DNA and RNA.
• Cadaverine NH2CH2CH2CH2CH2CH2NH2
  (pentamethylendiamine). It is liquid. It is
  formed in the process of rotting of corpses like
  putrescin.
• Aniline C6H5NH2. It is colourless liquid with
  peculiar smell. It is poisonous. It is used in
  the process of synthesis of dyes, medicines,
  plastic materials.
• Phenamine C6H5CH2CH(NH2)CH3 (1-phenylpropanamine-2
  ). It is white crystal solid. It is used as
  stimulator of CNS.

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13. Aminoalcohols

• Aminoalcohols are the derivatives of
  hydrocarbons which contain aminogroup in their
  molecule. For aminoalcohols it is used the
  nomenclature according to which the location of
  aminogroup is denoted by number or Greek letter.
• Isomery of aminoalcohols is similar to isomery
  of disubstituted hydrocarbons.

2-aminoethanol or ß-aminoethyl alkohol
2-N-methylaminoethanol
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14. The methods of extraction of aminoalcohols

1. Joining of ammonium or amines to a-oxides
2. Reduction of nitroalcohols
3. Reaction of halogenalcohols with ammonium or
   amines

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15. Chemical properties of aminoalcohols

• Chemical properties of aminoalcohols are
  specified by the presence of OH and aminogroups
  in the structure of its molecules. Aminoalcohols
  have basic reaction.
• 1. Reaction with acids
• 2.Reaction with SOCl2

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16. Arylamines

• Arylamines are the derivatives of ammonium. In
  its molecule one, two or three hydrogen atoms are
  substituted to aromatic radicals. The names of
  arylamines depend on the presence of aromatic
  radicals and their locations.

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• Arylamines Aniline, like alkylamines, has a
  pyramidal arrangement of bonds around nitrogen,
  but its pyramid is somewhat shallower. One
  measure of the extent of this flattening is given
  by the angle between the carbonnitrogen bond and
  the bisector of the H-N-H angle.

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• For sp³-hybridized nitrogen, this angle (not the
  same as the C-N-H bond angle) is 125, and the
  measured angles in simple alkylamines are close
  to that. The corresponding angle for sp²
  hybridization at nitrogen with a planar
  arrangement of bonds, as in amides, for example,
  is 180. The measured value for this angle in
  aniline is 142.5, suggesting a hybridization
  somewhat closer to sp³ than to sp². The structure
  of aniline reflects a compromise between two
  modes of binding the nitrogen lone pair (Figure
  22.3).
• FIGURE 22.3 Electrostatic potential maps of the
  aniline in which the geometry at nitrogen is (a)
  nonplanar and (b) planar.

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• The electrons are more strongly attracted to
  nitrogen when they are in an orbital with some s
  characteran sp³-hybridized orbital, for example
  than when they are in a p orbital. On the other
  hand, delocalization of these electrons into the
  aromatic p system is better achieved if they
  occupy a p orbital. A p orbital of nitrogen is
  better aligned for overlap with the p orbitals of
  the benzene ring to forman extended p system than
  is an sp³-hybridized orbital. As a result of
  these two opposing forces, nitrogen adopts an
  orbital hybridization that is between sp³ and
  sp². The corresponding resonance description
  shows the delocalization of the nitrogen
  lone-pair electrons in terms of contributions
  from dipolar structures. In the nonplanar
  geometry, the unshared pair occupies an sp³
  hybrid orbital of nitrogen. The region of highest
  electron density in (a) is associated with
  nitrogen. In the planar geometry, nitrogen is
  sp²-hybridized and the electron pair is
  delocalized between a p orbital of nitrogen and
  the p system of the ring. The region of highest
  electron density in (b) encompasses both the ring
  and nitrogen.

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• The actual structure combines features of both
  nitrogen adopts a hybridization state between sp³
  and sp².
• The orbital and resonance models for bonding in
  arylamines are simply alternative ways of
  describing the same phenomenon. Delocalization of
  the nitrogen lone pair decreases the electron
  density at nitrogen while increasing it in the p
  system of the aromatic ring. Weve already seen
  one chemical consequence of this in the high
  level of reactivity of aniline in electrophilic
  aromatic substitution reaction. Other ways in
  which electron delocalization affects the
  properties of arylamines are described in later
  sections of this chapter.

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• The derivatives of toluene are called toluidines

o-toluidine m-toluidine
p-toluidine benzylamine
N-methylaniline
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17. The methods of extraction of aromatic amines

• Recovery of nitroarenes (Zinin reaction)

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• II. Reaction of halogenarenes with ammonium and
  amines.

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• III. Alkylation of primary aromatic amines

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18. Physical properties of aromatic amines

• Aromatic amines are colourless liquids or solids
  with peculiar smell. They can be oxidized by open
  air very easily. Aromatic amines are very toxic
  compounds. Hydrogen bonding significantly
  influences the properties of primary and
  secondary amines. Thus the boiling point of
  amines is higher than those of the corresponding
  phosphines, but generally lower than those of the
  corresponding alcohols. Thus methylamine and
  ethylamine are gases under standard conditions,
  whereas the corresponding methyl alcohol and
  ethyl alcohols are liquids. Gaseous amines
  possess a characteristic ammonia smell, liquid
  amines have a distinctive "fishy" smell. Also
  reflecting their ability to form hydrogen bonds,
  most aliphatic amines display some solubility in
  water. Solubility decreases with the increase in
  the number of carbon atoms. Aliphatic amines
  display significant solubility in organic
  solvents, especially polar organic solvents.
  Primary amines react with ketones such as
  acetone, and most amines are incompatible with
  chloroform and carbon tetrachloride. The aromatic
  amines, such as aniline, have their lone pair
  electrons conjugated into the benzene ring, thus
  their tendency to engage in hydrogen bonding is
  diminished. Their boiling points are high and
  their solubility in water low

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4.Comparative structure of aromatic and aliphatic
amines.
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19. Chemical properties of aromatic amines

• Reaction with acids
• Alkylation

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• 3. Acylation (reaction with halogenanhydrides or
  anhydrides of carbon acids). In the result of
  this reaction acylderivatives are formed.
• Acylderivatives are used as antipyretic means.

paracetomol phenacethine
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• 4. Qualitative reaction to primary aminogroup
• The peculiar smell of C6H5CN is felt in the
  result of this reaction.
• 5. Reaction with HNO2. If primary, secondary and
  tertiary arylamines react with HNO2 different
  products can form.
• a) primary arylamines

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• b) secondary arylamines
• c) tertiary arylamines

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• 6. Reaction with aromatic aldehyds - formation
  azomethans (Schiff bases) - quality response.
• 7. Halogenation (white precipitate forms).

N-benzylidenaniline
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8.Nitration reaction - reaction of transmitting,
making protection of amino groups.
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• 9. Oxidation

hinonimin
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nitrozobenzene
N
H
N
O
2
2
O
CF3COOOH
nitrobenzene
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• 10. Reaction with H2SO4
• The product of this reaction is called
  sulphanilic acid.

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• 20. Sulphanilic acid
• Sulphanilic acid has acidic (-SO3H) and
  alkaline (-NH2) centers in its molecule.
  Sulphanilic acid is quite active acid. It easily
  forms salts with alkalis. But it does not react
  with mineral acids. Although it has alkaline
  (-NH2) group it does not have alkaline
  properties.
• Sulphanilic acid is widely used in production
  of some medicines and dyes. It is the structural
  part of a large group of medicines which have
  antibacterial action. They are called
  sulphanylamides. The basic compound of all
  sulphanylamides is streptocide. It is amide of
  sulphanilic acid

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• 21. The synthesis of streptocide
• The synthesis of streptocide consists of 4
  stages
• Acylation
• acetanilide
• 2. Sulphochloration

p-chlorsulfonilacetanilide
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• 3. Amidation
• 4. Hydrolysis

p-sulfamoilacetanilide
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• Streptocide has amphoteric properties

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22.Sulphanylamidic preparations

• Sulfanilamide is a molecule containing the
  sulfonamide functional group attached to an
  aniline. Sulfanilamide is a sulfonamide
  antibiotic. The sulfonamides are synthetic
  bacteriostatic antibiotics with a wide spectrum
  against most gram-positive and many gram-negative
  organisms. However, many strains of an individual
  species may be resistant. Sulfonamides inhibit
  multiplication of bacteria by acting as
  competitive inhibitors of p-aminobenzoic acid in
  the folic acid metabolism cycle. Bacterial
  sensitivity is the same for the various
  sulfonamides, and resistance to one sulfonamide
  indicates resistance to all. Most sulfonamides
  are readily absorbed orally. However, parenteral
  administration is difficult, since the soluble
  sulfonamide salts are highly alkaline and
  irritating to the tissues. The sulfonamides are
  widely distributed throughout all tissues. High
  levels are achieved in pleural, peritoneal,
  synovial, and ocular fluids. Although these drugs
  are no longer used to treat meningitis, CSF
  levels are high in meningeal infections. Their
  antibacterial action is inhibited by pus.
  Mechanism of action Sulfanilamide is a
  competitive inhibitor of bacterial
  para-aminobenzoic acid (PABA), a substrate of the
  enzyme dihydropteroate synthetase. The inhibited
  reaction is necessary in these organisms for the
  synthesis of folic acid. Indication For the
  treatment of vulvovaginitis caused by Candida
  albicans

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• Sulphanylamidic preparations. All
  sulphanylamidic medicines contain the next
  fragment
• Albucyde (sulphacyl) is an antibacterial mean,
  is a part of eye-drops.
• Urosulphane is an antibacterial mean by
  infection of urinal canals.
• Norsulphazol is used by pneumonia, meningitis,
  staphylococcal and streptococcal sepsis,
  infectious diseases.
• Bucarbane is a hypoglycemic mean.

Albucyde Urosulphane Norsulphazol
Bucarbane (sulphacyl)
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23. Medicinal preparations (derivates of
p-aminobenzoic acid (pABA).
Anaesthesine procaine (novocaine) hydrochloride
mefenaminic acid
Anaesthesine is used as an 5-10 ointment or
powder by wounds, urticaria or skin diseases
which are characterized by itching. Procaine
(novocaine) hydrochloride is a local
anaesthetic. Mefenaminic acid is an
anaesthetic substance, antiinflamed and
antipyretic mean, is used by parodontosis.
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• 4-Aminobenzoic acid (also known as
  para-aminobenzoic acid or PABA) is an organic
  compound with the molecular formula C7H7NO2. PABA
  is a white crystalline substance that is only
  slightly soluble in water. It consists of a
  benzene ring substituted with an amino group and
  a carboxyl group. PABA is an essential nutrient
  for some bacteria and is sometimes called Vitamin
  Bx. In humans, PABA is normally made by E. coli
  in the colon and therefore PABA from food is not
  normally essential to human health. PABA is
  therefore not officially classified as a vitamin.
  PABA is an intermediate in bacterial synthesis of
  folate. Although humans lack the ability to
  synthesize folate from PABA, that is also
  normally done by E. coli. PABA is sometimes
  marketed as an essential nutrient for use
  whenever normal PABA synthesis by intestinal
  bacteria is insufficient.

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• Medical use of 4-Aminobenzoic acid (also known
  as para-aminobenzoic acid or PABA)
• The potassium salt is used as a drug against
  fibrotic skin disorders, such as Peyronie's
  disease, under the trade name Potaba. PABA is
  also occasionally used in pill form by sufferers
  of Irritable bowel syndrome to treat its
  associated gastrointestinal symptoms, and in
  nutritional epidemiological studies to assess the
  completeness of 24-hour urine collection for the
  determination of urinary sodium, potassium, or
  nitrogen levels.

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24. Diazocompounds

• Diazocompounds are organic compounds that
  contain NN-group which is connected with
  hydrocarbon radical and radical of mineral acid.
  The general formula of diazocompounds is
• RN2X, where
• R is a hydrocarbon radical
• X is a radical of mineral acid (Cl-, Br-,
  NO3-, SO4H-, OH-, CN-, SO3H-, SH-.
• There are aliphatic and aromatic diazocompounds.
  But aromatic diazocompounds are more important
  for production of dyes and medicines, in
  pharmaceutical analysis.
• The general formula of aromatic diazocompounds
  is
• ArN2X, where
• Ar is an aromatic radical
• X is a radical of mineral acid (Cl-, Br-,
  NO3-, SO4H-, OH-, CN-, SO3H-, SH-.

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• In acid medium aromatic diazocompounds have
  ionic structure and they are called salts of
  diazonium (ArNNX-). In neutral medium aromatic
  diazocompounds have covalent structure
  (ArNNX). In alkaline medium aromatic
  diazocompounds are diazotates.

acid medium
neutral medium
alkaline medium
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• The systematic (IUPAC) name of aromatic
  diazocompounds is obtained by adding the suffix
  -diazo-or -dizonium- (in the case of salts of
  diazonium). For example
• Physical properties salts of diazonium
• Salts of diazonium are colorless crystalline
  substance, easily soluble in water. They are
  unstable on heating and mechanical actions of
  explosion.That why decomposed in reactions
  usually use them freshly prepared aqueous
  solutions

benzenediazohydroxide sodium benzenediazotate
4-chlorobenzenedizocyanide
4-methylbenzenediazonium chloride
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25. The methods of extraction of aromatic
diazocompounds

1. Reaction of diazotation
2. Reaction of aromatic amines with alkylnitrites

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Reaction mechanism of diazotation
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26. Chemical properties of aromatic
diazocompounds

• I. Reaction with extraction of N2

KBr
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• II. Reaction without extraction of N2
• a) Formation of diazoderivatives
• C6H5NNCl 2NaOH ? C6H5NNONa NaCl H2O
• C6H5NNCl CH3NH2 ? C6H5NNNHCH3 HCl
• C6H5NNCl NaCN ? C6H5NNCN NaCl
• b) Reduction (catalysts are SnCl2 and HCl)
  
  
  
  H
• C6H5NNCl 2SnCl2 4HCl ? C6H5NH NH2HCl
  2SnCl4

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• c) Reaction of azojoining
• III. Reactions of substitution
• C6H5NNCl HOH ? C6H5OH N2 HCl
• C6H5NNCl KI ? C6H5I N2 KCl
• C6H5NNCl H3PO2 HOH ? C6H6 N2 HCl
  H3PO3

4- aminoazobenzene
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27.Azocompounds

• Azocompounds are organic compounds that contain
  -NN-group which is connected with 2 hydrocarbon
  radicals.
• There are aliphatic and aromatic azocompounds.
• Physical properties of azocompounds
• Azocompounds are crystalline substances,
  colored in yellow, orange, red, blue and other
  colors. This feature allows you to use many of
  them as a means of chemotherapeutic means

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• 28.The methods of extraction of aromatic
  azocompounds.
• 1. Formation of diazoderivatives
• C6H5NNCl 2NaOH ? C6H5NNONa NaCl H2O
• C6H5NNCl CH3NH2 ? C6H5NNNHCH3 HCl
• C6H5NNCl NaCN ? C6H5NNCN NaCl
• 2. Reduction nitroarenes in alkaline medium
  (reaction with Zn NaOH) .

H C6H5NO2 ?
C6H5NNC6H5
azobenzene
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29. Chemical properties of aromatic azocompounds

• Chemical properties are specified by group NN
• 1.Reaction with mineral acids
• C6H5NNC6H5 HCl ? C6H5NHNC6H5 Cl
• 2. Oxidation (reaction with peroxiacids)
  
  
  O
• C6H5NNC6H5 ? C6H5NO NC6H5
• 3.Reduction (reaction with Zn NaOH)
  
  
  2H
• C6H5NNC6H5 ? C6H5NHNHC6H5

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30. Physical bases of theory of colouration.

• The theory of colouration studies the dependence
  of colour of organic compounds on the structure
  of molecules. The colour of any compound is
  specified its ability to absorb electromagnetic
  radiation. Color or colour (see spelling
  differences) is the visual perceptual property
  corresponding in humans to the categories called
  red, yellow, blue and others. Color derives from
  the spectrum of light (distribution of light
  energy versus wavelength) interacting in the eye
  with the spectral sensitivities of the light
  receptors. Color categories and physical
  specifications of color are also associated with
  objects, materials, light sources, etc., based on
  their physical properties such as light
  absorption, reflection, or emission spectra.

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• Structural fragments of molecule which cause the
  certain colour are called chromophores. The main
  chromophores are the next groups
• NN
• NO2
• NO
• In the structure of molecule there are groups
  which can amplify the colour of compound. They
  are called auxochromes. They are the next groups
• 1)OH 2) NH2
• 3) NHR 4) NR2
• 5)OR 6) SH

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The colors of the visible light spectrum The colors of the visible light spectrum The colors of the visible light spectrum
color wavelength interval frequency interval
red 700635 nm 430480 THz
orange 635590 nm 480510 THz
yellow 590560 nm 510540 THz
green 560490 nm 540610 THz
blue 490450 nm 610670 THz
violet 450400 nm 670750 THz
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Color, wavelength, frequency and energy of light Color, wavelength, frequency and energy of light Color, wavelength, frequency and energy of light Color, wavelength, frequency and energy of light Color, wavelength, frequency and energy of light Color, wavelength, frequency and energy of light
Color ?/nm ?/1014 Hz ?b/104 cm-1 E/eV E/kJ mol-1
Infrared gt1000 lt3.00 lt1.00 lt1.24 lt120
Red 700 4.28 1.43 1.77 171
Orange 620 4.84 1.61 2.00 193
Yellow 580 5.17 1.72 2.14 206
Green 530 5.66 1.89 2.34 226
Blue 470 6.38 2.13 2.64 254
Violet 420 7.14 2.38 2.95 285
Near ultraviolet 300 10.0 3.33 4.15 400
Far ultraviolet lt200 gt15.0 gt5.00 gt6.20 gt598
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• In the 1969 study Basic Color Terms Their
  Universality and Evolution, Brent Berlin and Paul
  Kay describe a pattern in naming "basic" colors
  (like "red" but not "red-orange" or "dark red" or
  "blood red", which are "shades" of red). All
  languages that have two "basic" color names
  distinguish dark/cool colors from bright/warm
  colors. The next colors to be distinguished are
  usually red and then yellow or green. All
  languages with six "basic" colors include black,
  white, red, green, blue and yellow. The pattern
  holds up to a set of twelve black, grey, white,
  pink, red, orange, yellow, green, blue, purple,
  brown, and azure (distinct from blue in Russian
  and Italian but not English).

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• 31.Azo dyes
• Azo dyes are dyes with -NN- azo structure as a
  chromophore.
• Methyl orange is a pH indicator frequently used
  in titrations. It is often chosen to be used in
  titrations because of its clear colour change.
  Because it changes colour at the pH of a
  mid-strength acid, it is usually used in
  titrations for acids. Unlike a universal
  indicator, methyl orange does not have a full
  spectrum of colour change, but has a sharper end
  point.

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• In a solution becoming less acidic, methyl
  orange moves from red to orange and finally to
  yellow with the reverse occurring for a solution
  increasing in acidity. It should be noted that
  the entire colour change occurs in acidic
  conditions.
• In an acid it is reddish and in alkali it is
  yellow.

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• Methyl red, also called C.I. Acid Red 2, is an
  indicator dye that turns red in acidic solutions.
  It is an azo-dye, and is a dark red crystalline
  powder. Methyl red is a pH indicator it is red
  in pH under 4.4, yellow in pH over 6.2, and
  orange in between, with a pKa of approximately 5.
• Preparation of methyl red
• As an azo dye, methyl red may be prepared by
  diazotization of anthranilic acid, followed by
  reaction with dimethylaniline

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• Methyl yellow, or C.I. 11020, is a chemical
  compound which may be used as a pH indicator.
• In aqueous solution at low pH, methyl yellow
  appears red. Between pH 2.9 and 4.0, methyl
  yellow undergoes a transition, to become yellow
  above pH 4.0. Additional indicators are listed in
  the article on pH indicators. As "butter yellow"
  the agent had been used as a food additive before
  its toxicity was recognized.

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Thank you for attention!