Untitled Quiz

Pharmaceutical Organic Chemistry I (PMC 102)

• Course taught by Dr. Asmaa Yassen at GALALA UNIVERSITY, powered by Arizona State University.
• Course website: gu.edu.eg

Classification of Carbon Atoms

• Primary (1°): A carbon atom bonded to one other carbon atom.
• Secondary (2°): A carbon atom bonded to two other carbon atoms.
• Tertiary (3°): A carbon atom bonded to three other carbon atoms.
• Quaternary (4°): A carbon atom bonded to four other carbon atoms.

Alkanes

• Saturated hydrocarbons, containing only single bonds.
• General formula: C_nH_2n+2.
• Nomenclature follows specific rules.
  • Root word + ane
• Examples: methane (CH₄), ethane (C₂H₆), propane (C₃H₈), butane (C₄H₁₀), pentane (C₅H₁₂), etc

Alkane: Physical Properties

• C₁-C₅ are gases at room temperature.
• C₆-C₁₀ are liquids.
• Above C₁₁ are semisolids or waxy matters.
• Insoluble in water, but soluble in nonpolar solvents.
• Boiling point increases with increasing molecular weight.
• Boiling point decreases with branching.

Alkane: Nomenclature

• For substituted alkanes, identify the longest continuous carbon chain.
• Number the chain from the end nearest the substituent.
• Name and locate each substituent group.
• List substituent groups alphabetically, using prefixes (di, tri, etc.) for multiple occurrences of the same group.

Alkyl Groups

• Alkyl groups are derived from alkanes by removing one hydrogen atom.
  • CH₃ - Methyl
  • CH₃CH₂ - Ethyl
  • Isopropyl, sec-butyl, tert-butyl

Halogenation of Alkanes

• Free radical substitution reaction (requires light or heat).
• Stability of carbon radicals follows the order: tertiary > secondary > primary.

Cycloalkanes

• A class of hydrocarbons with carbon atoms forming a ring structure.
• General formula: C_nH_2n
• More reactive than open-chain alkanes due to ring strain.
• Nomenclature includes the prefix "cyclo."

Nomenclature of substituted cycloalkanes

• Number the ring atoms to give substituents the lowest possible numbers.
• List substituents alphabetically.

Preparation of cycloalkanes

• A dihalogen compound is dehalogenated using Zn and Nal catalyst.

Reduction of Aromatic compounds

• Treatment of benzene and its derivatives with hydrogen gas (H₂) in the presence of a catalyst(Ni) at 150-200°C forms cyclohexane

Angle Strain

• Deviation from the ideal bond angle (109.5°) in cycloalkanes leads to increased strain and reactivity.
• Cyclopropane has significant strain, while cyclopentane and cyclohexane have less (or no) strain.

Alkenes:

• Unsaturated hydrocarbons.
• Contain one or more carbon-to-carbon double bonds (C=C).
• General formula: C_nH_2n
• Nomenclature rules include adding "-ene" to the root name, and numbering the double bond to the lowest possible numbers.
• Classification of alkenes is based on the degree of substitution on the carbon atoms bonded to the double bond (mono-, di-, tri-, or tetrasubstituted).

Alkynes:

• Unsaturated hydrocarbons containing one or more carbon-to-carbon triple bonds (C≡C).
• General formula: C_nH_2n-2.
• Nomenclature rules include adding "-yne" to the root name and numbering the triple bond to the lowest possible number.
• Terminal alkynes have a hydrogen atom on one of the triple bonded carbons. Internal alkynes have carbon atoms bound to each carbon of the triple bond.

Properties of Alkynes

• Physical properties similar to corresponding alkanes and alkenes.
• Up to four carbons are gases at room temp.
• Relatively nonpolar. Dissolve in nonpolar solvents and low polarity solvents.
• Terminal alkynes are weakly acidic.

Reactions of alkynes

• Addition reactions are possible with one or two molar equivalents of a reagent.
• Hydrogenation (adding H₂) can result in an alkene or an alkane.
• Partial reduction with Lindlar catalyst results in cis-alkenes.
• Reduction to trans-alkenes using Na or Li in liquid NH₃.
• Addition of halogens (Br₂, Cl₂) results in di-, tetra-halogenated products.
• Addition of hydrogen halides (HCl, HBr) follows Markovnikov's rule.
• Anti-Markovnikov addition possible with peroxides in presence of HBr.
• Addition of water using HgSO₄ in presence of H₂SO₄ forms ketones.
• Ozonolysis (treating with ozone and a reducing agent) cleaves the triple bond resulting in carboxylic acids.

Isomers of Alkenes

• Geometric isomers (cis-trans) exist when the two carbons bonded to the double bond have different groups attached.
• Numbering of substituents is important for determining the E/Z configuration.