Unusual Functional Groups in Organic Chemistry

Alkanes and Cycloalkanes

• Alkanes: Saturated hydrocarbons. Example: Pentane (C5H12).
• Cycloalkanes: Form cyclic structures. Example: Cyclopentane (C5H10), unsaturated with an Index of Hydrogen Deficiency (IHD) of 1.
• Bicycloalkanes: Two rings present, giving an IHD of 2.

Alkenes and Dienes

• Alkenes: Unsaturated hydrocarbons with double bonds (IHD = 1 per double bond).
• Dienes: Molecules with two double bonds.
  • Conjugated Dienes: Alternating single and double bonds.
  • Cumulated Dienes (Allene): Double bonds adjacent to each other.
  • Isolated Dienes: Double bonds are far apart.

Alkynes

• Alkynes: Contain triple bonds with an IHD of 2.
  • Internal Alkyne: Triple bond in the middle of the chain.
  • Terminal Alkyne: Triple bond at the end of the chain.

Aromatic Compounds

• Benzene: Aromatic ring with IHD of 4 (C6H6).
• Phenyl Group: Benzene as a substituent in larger molecules.
• Benzene Intermediate: Found in nucleophilic aromatic substitution reactions.

Alcohols and Thiols

• Primary Alcohols: OH group on primary carbon.
• Diol: Two hydroxyl groups, often referred to as a "CIS diol."
• Thiols: Contain sulfur; prefix "thiol" indicates sulfur presence.

Bases in Organic Chemistry

• Hydroxide (OH-): Strong base.
• Alkoxide (RO-): Similar to hydroxide but with an R group.
• Thiolate Ion (SR-): Analogous to alkoxide but with sulfur.

Ethers and Sulfides

• Ethers (ROR): Oxygen between two R groups.
• Thioethers (RSR): Sulfur replacing the oxygen in an ether.
  • Disulfides: Two sulfur atoms in a bridge between carbons.

Peroxides

• Hydrogen Peroxide (H2O2): Known for radical reactions.
• Organic Peroxides: Highly reactive.

Epoxides and Oxanes

• Epoxides: Three-atom ring with oxygen.
• Oxiranes (Arene Oxides): Related to benzene.
• Oxetanes: Four-atom ring with oxygen.
• Dioxanes: Rings containing two oxygen atoms.

Crown Ethers

• Crown Ethers: Cyclic compounds that can solvate ions:
  • 12-Crown-4: Solvates lithium ions.
  • 15-Crown-5: Solvates sodium ions.
  • 18-Crown-6: Solvates potassium ions.

Aldehydes and Ketones

• Aldehydes: Contain a CHO group.
• Ketones: Two R groups attached to the carbonyl.
• Alpha-beta Unsaturated Aldehydes/Ketones: Double bond between alpha and beta carbons (enol and enone).

Lactams and Lactones

• Lactones: Cyclic esters.
• Lactams: Cyclic amides.

Acids and Anhydrides

• Carboxylic Acids: R-COOH with acidic properties.
• Acid Anhydrides: Derived from two carboxylic acids.

Complexes with Sulfur and Phosphorus

• Sulfones and Sulfides: Sulfur-containing functional groups.
• Phosphate and Phosphonate Esters: Relevant in biochemical contexts.

Amines and Amides

• Amines: Defined by carbon attachments; primary, secondary, tertiary.
• Amides: Contain carbonyl neighboring amines.

Nitro and Nitroso Compounds

• Nitro Group (NO2): Contains nitrogen and oxygen double bonds.
• Nitroso Group (NO): Contains nitrogen and oxygen in a single bond.

Cyanides and Isocyanides

• Nitriles (RCN): Carbon triple-bonded to nitrogen.
• Isocyanides (NC-R): Carbon and nitrogen switch positions.
• Thiocyanates (R-SCN) and Isothiocyanates (R-NCS): Sulfur-containing analogs.

Halides and Hydrates

• Halo Hydrins: Halogen and hydroxyl group on adjacent carbons.
• Cyano Hydrins: Cyanide and hydroxyl group on the same carbon.

Miscellaneous Functional Groups

• Carbamate: Ester and amide hybrid.
• Carbonates: Esters with carbonic acid.

Applications in Chemistry

• Alpha Hydroxy Acids (AHAs): Used in skin care products for exfoliation.
• Beta Hydroxy Acids (BHAs): Milder than AHAs, used similarly.
• Amino Acids: Building blocks of proteins, differing by functional group positioning.

These notes cover various unusual and important functional groups in organic chemistry, crucial for understanding complex organic reactions and compounds.