Alcohol (Functional Group) Chemical Structure

1. Identification

Summary

Alcohol (functional group) denotes an sp³ carbon bearing a hydroxyl (–OH) substituent: general formula R–OH. Hallmarks: hydrogen bonding, moderate nucleophilicity of the oxygen lone pairs, weak Brønsted acidity (pKₐ ~15–19), and formation of derivatives (ethers, esters, sulfonates).

Brand Names

Not applicable.

Name

Alcohol (hydroxyl functional group)

Background

Classified by substitution at the α-carbon (primary, secondary, tertiary). Physical trends: higher boiling points vs hydrocarbons due to H-bonding; miscibility with water decreases with increasing hydrophobic R. Spectroscopy: IR O–H stretch ~3200–3600 cm⁻¹ (broad), C–O stretch ~1000–1200 cm⁻¹; ¹H NMR O–H often broad/variable; ¹³C NMR C–O at 50–80 ppm.

Modality

Functional group (class of small molecules)

Groups

Endogenous metabolites and exogenous chemicals

Structure

Generic alcohol (R–OH) showing hydroxyl; polar, hydrogen-bonding functional group used across organic and medicinal chemistry.
Alcohol functional group (hydroxyl), generic 2D structure R–OH with hydrogen bonding concept

Weight

Not applicable (class-dependent)

Chemical Formula

R–OH

Synonyms

Hydroxyl group; alkanol; –OH

External IDs

Not applicable (generic functional group)


2. Pharmacology

Indication

Not a therapeutic agent (group descriptor).

Associated Conditions

Occurs in biomolecules (sugars, steroids, amino-acid side chains) and countless APIs; often masked as esters/ethers to tune ADME.

Associated Therapies

Medicinal chemistry prodrug strategies (e.g., ester prodrugs to enhance permeability).

Contraindications & Blackbox Warnings

Not applicable at the group level.

Pharmacodynamics

Chemical behavior: nucleophilic substitution at the α-carbon (after activation), esterification with acids/acid derivatives, oxidation (primary→aldehyde/acid; secondary→ketone; tertiary: resistant), dehydration to alkenes (E1/E2), and formation of sulfonate leaving groups (tosylate/mesylate).

Mechanism of action

Reactivity arises from the polar O–H and σ C–O bonds; lone pairs on oxygen participate in Lewis basic interactions and metal coordination; H-bond donor/acceptor behavior governs solvation, binding, and boiling point elevation.

Absorption

Ionization rare (weak acid), but extensive H-bonding increases aqueous solubility vs hydrocarbons of similar size.

Volume of distribution / Protein binding / Metabolism / Elimination / Half-life / Clearance

Not applicable at the class level; scaffold-dependent.

Adverse Effects / Toxicity / Pharmacogenomics

Not applicable to the functional group per se.

Pathways

Conversions: ROH → RCl/RBr (PX₃, SOCl₂), ROH → ROTs/OMs (leaving-group install) → SN2; Fischer esterification (ROH + R′CO₂H ⇄ R′CO₂R); oxidations (PCC/Swern/DMP; catalytic O₂); Williamson ether synthesis (RO⁻ + R′X).


3. Interactions

Chemical Interactions

Acid–base with strong bases (RO⁻ formation), metal alkoxides with Na/K, acetal/ketal formation via carbonyl chemistry (after oxidation/derivatization), and coordination to Lewis acids/cations.

Food/Drug Interactions

Not applicable to the group.


4. Categories

ATC Codes

None (functional group)

Drug Categories

Functional group; Polar protic motif

Chemical Taxonomy

sp³ carbon–oxygen single bond with terminal hydroxyl; generic notation R–OH; hydrogen-bond donor/acceptor; IR O–H ~3200–3600 cm⁻¹.

Affected organisms

Not applicable


5. Chemical Identifiers

UNII / CAS / InChI / InChIKey

Not applicable (class).
Generic SMILES: R–O

IUPAC Name

Alcohol functional group (hydroxyl group)


6. References

IUPAC Gold Book — definitions of alcohols and hydroxyl group; spectroscopic conventions.
Clayden, Greeves, Warren. Organic Chemistry — alcohol reactivity (oxidation, substitution, dehydration), physical properties.
March’s Advanced Organic Chemistry — mechanisms of esterification, sulfonate formation, and redox of alcohols.
Silverstein et al. Spectrometric Identification of Organic Compounds — IR/NMR signatures of alcohols.

Leave a Comment