4-Isopropyl-2-methoxy-1-methylbenzene (CAS 6379-73-3) — Woody Heart to base Note Fragrance Ingredient
4-Isopropyl-2-methoxy-1-methylbenzene
CAS 6379-73-3
What Is 4-Isopropyl-2-methoxy-1-methylbenzene?
4-Isopropyl-2-methoxy-1-methylbenzene is a synthetic fragrance ingredient used in perfumes and scented products. It contributes a woody, spicy character often found in masculine fragrances and household cleaners. This molecule matters because it provides stability and longevity to fragrance compositions, acting as a versatile modifier that bridges fresh top notes with deeper base accords.
Safety Profile
GENERALLY SAFEWhat Does 4-Isopropyl-2-methoxy-1-methylbenzene Smell Like?
A robust aromatic with a dual personality – opens with crisp, almost camphoraceous pine notes that quickly settle into a warm, peppery heart. The dry-down reveals a dry woodiness reminiscent of aged cedar chests, with subtle vanilla-like sweetness emerging after several hours. Acts like a chameleon, amplifying citrus in top notes while anchoring spicy accords with its persistent backbone.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a woody-spicy bridge between the fresh bergamot top and ambroxan base, adding depth without overpowering the signature metallic freshness.
Provides subtle peppery warmth in the heart accord, complementing the ginger note while enhancing the sandalwood dry-down.
2D Molecular Structure
SMILES: COC1=CC(=CC=C1C)C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
A methoxy-substituted benzene derivative belonging to the aryl alkyl ether class. Synthesized through Friedel-Crafts alkylation of cresol derivatives followed by Williamson ether synthesis. The isopropyl group creates steric hindrance that influences volatility and odor persistence. No chiral centers present in this configuration.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Estimated 230-250°C |
| Density | ~0.95 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | Used as supporting note |
| Functional Fragrance | 0.5-2% | Up to 3% | Adds woody depth to cleaners |
Classic Accords
Tip: Use with citrus top notes to prevent the dry-down from becoming too heavy.
Alternatives & Comparisons
When more pronounced clove-like spice is desired, though requires careful dosing due to allergen potential.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No current restrictions under IFRA standards.
RIFM Assessment
Not currently evaluated by RIFM – considered low priority due to limited use volume.
Sustainability
As a synthetic material, production requires petrochemical feedstocks but avoids agricultural land use. Modern manufacturing typically employs catalytic processes with good atom economy. No known ecological toxicity at usage levels.
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References
- Bauer et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 6379-73-3Physical Properties
| Molecular Weight | 164.24 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.4🔬 PubChem |
| Boiling Point | 223 °C🔬 EPA CompTox |
| Vapor Pressure | 0.2692 mmHg @ 25°C📊 OPERA |
| Flash Point | 74.2 °C🔬 EPA CompTox |
| Involatility Index | 0.0226💻 Calculated |
| log Kp (skin permeability) | -1.288💻 Calculated |
| SMILES | CC1=C(C=C(C=C1)C(C)C)OC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 1.1 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | greenherbalphenolicspicy• leffingwell |
| Functional Groups | etheraromatic💻 RDKit |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID0047400
Physical Properties
| Molecular Weight | 164.248 g/mol🔬 EPA CompTox |
| Density | 0.923 g/cm^3📊 OPERA |
| Boiling Point | 223.713 °C📊 OPERA |
| Melting Point | -3.325 °C📊 OPERA |
| Flash Point | 79.153 °C📊 OPERA |
| Refractive Index | 1.49 Dimensionless📊 OPERA |
| Molar Volume | 179.783 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.078 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.078 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.078 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.23 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.165 mmHg📊 OPERA |
| Viscosity | 2.193 cP📊 OPERA |
| Surface Tension | 29.836 dyn/cm📊 OPERA |
| Thermal Conductivity | 124.583 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 9.23 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 2 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 51.941 cm^3/mol📊 OPERA |
| Polarizability | 20.591 Å^3📊 OPERA |
Data Sources:
🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.
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