3,5-Dichloro-4-methoxybenzoic acid
[CAS 37908-97-7]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives
• Name: 3,5-Dichloro-4-methoxybenzoic acid
• Synonyms: 3,5-Dichloro-p-anisic acid
• Molecular Formula: C₈H₆Cl₂O₃
• Molecular Weight: 221.04
• CAS Registry Number: 37908-97-7
• EC Number: 657-342-4
• SMILES: COC1=C(C=C(C=C1Cl)C(=O)O)Cl

Properties

• Solubility: Very slightly soluble (0.11 g/L) (25 °C), Calc.^*
• Density: 1.474±0.06 g/cm³ (20 °C 760 Torr), Calc.^*
• Melting point: 202 °C (Expl.)
• Boiling point: 328.9±37.0 °C 760 mmHg (Calc.)^*
• Flash point: 152.7±26.5 °C (Calc.)^*
• Index of refraction: 1.577 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H319
• Safety Statements: P264-P264+P265-P270-P280-P301+P317-P305+P351+P338-P330-P337+P317-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319

chemBlink Chemical Story

3,5-Dichloro-4-methoxybenzoic acid (CAS 37908-97-7) is a substituted aromatic carboxylic acid bearing two chlorine atoms symmetrically around a methoxy group. The carboxyl group provides a versatile point for conversion to acid chlorides, esters, amides, and other derivatives, while the chloro and methoxy substituents tune steric bulk, lipophilicity, and electronic character of the aromatic ring. The compound is directly related to 3,5-dichloro-4-methoxybenzoyl chloride: activation of this acid can produce the corresponding acid chloride for acyl-transfer chemistry. Public exact-CAS sources mainly identify it as a synthetic or pharmaceutical intermediate rather than a finished active ingredient. Its chemical significance lies in serving as a preassembled substituted benzene fragment that can be incorporated into more complex structures.

Exact chemical identity matters because free forms, salts, stereoisomers, hydrates, metabolites, intermediates, and finished products can carry different registry numbers even when their names are closely related. These distinctions affect molecular weight, physical properties, analytical standards, formulation, and interpretation of literature. A reliable chemical database therefore follows the exact substance instead of automatically transferring every property of a related form.

Functional groups are also a map of intended reactivity. Carbonyls, alcohols, amines, halides, alkenes, and heterocycles provide different opportunities for bond formation, while hydrocarbon frameworks influence shape and solubility. In multistep synthesis, the usefulness of an intermediate often comes from being able to transform one position selectively while leaving another group available for a later operation.

Modern chemical development depends as much on characterization as on synthesis. Identity, purity, stereochemistry, water or salt content, and process-related impurities may all need control. Well-characterized intermediates and reference materials therefore matter even when they never become a final commercial product: they make complex manufacturing and research reproducible.

A responsible Chemical Story distinguishes documented use from structural possibility. A familiar molecular scaffold can suggest a hypothesis, but resemblance alone does not establish a biological target, approved indication, or commercial application. When exact-CAS literature is limited, verified chemistry and clearly documented uses are more informative than speculation.

Seen broadly, practical performance emerges from the whole molecular system. Structure, stereochemistry, physical form, synthetic route, reaction environment, and, for biological molecules, metabolism can all determine what a substance actually does. Connecting these details to a documented historical, industrial, or biological role turns a registry entry into a meaningful chemical story.

Exact chemical identity matters because free forms, salts, stereoisomers, hydrates, metabolites, intermediates, and finished products can carry different registry numbers even when their names are closely related. These distinctions affect molecular weight, physical properties, analytical standards, formulation, and interpretation of literature. A reliable chemical database therefore follows the exact substance instead of automatically transferring every property of a related form.

Functional groups are also a map of intended reactivity. Carbonyls, alcohols, amines, halides, alkenes, and heterocycles provide different opportunities for bond formation, while hydrocarbon frameworks influence shape and solubility. In multistep synthesis, the usefulness of an intermediate often comes from being able to transform one position selectively while leaving another group available for a later operation.

Modern chemical development depends as much on characterization as on synthesis. Identity, purity, stereochemistry, water or salt content, and process-related impurities may all need control. Well-characterized intermediates and reference materials therefore matter even when they never become a final commercial product: they make complex manufacturing and research reproducible.

References:
1. Specialist chemical catalogs. CAS 37908-97-7 identity.
2. General organic chemistry references on benzoic-acid activation and acyl derivatives.

Read more stories