trans-Tetrahydro-2-isobutyl-4-methylpyran-4-ol (CAS 65418-70-4) — Woody Heart to Base Note Fragrance Ingredient

Woody · Floral

trans-Tetrahydro-2-isobutyl-4-methylpyran-4-ol

CAS 65418-70-4

Origin
synthetic
Note
Heart to Base
IFRA
Use with awareness
Data as of: Apr 2026

What Is trans-Tetrahydro-2-isobutyl-4-methylpyran-4-ol?

trans-Tetrahydro-2-isobutyl-4-methylpyran-4-ol is a synthetic fragrance ingredient used in fine perfumery. It’s found in niche fragrances where a complex woody-floral character is desired. This molecule contributes depth and longevity to fragrance compositions, often acting as a bridge between top and heart notes.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
Approved for fragrance use
Limited safety data available
CAS
65418-70-4
Formula
Mixture
MW
Variable
Odor Family
Woody · Floral
Layer 1 · Enthusiast

What Does trans-Tetrahydro-2-isobutyl-4-methylpyran-4-ol Smell Like?

This synthetic molecule presents a sophisticated olfactory profile – imagine damp oak barrels infused with dried rose petals. The opening has a slightly metallic sharpness that quickly softens into a warm, woody heart with subtle floral undertones. As it dries down, it reveals a creamy-smooth base reminiscent of sandalwood oil, though more diffuse and less spicy. The overall effect is elegant and versatile, blending well with both floral and woody materials.

Scent Profile
Layer 2

2D Molecular Structure

rel-(2R,4S)-Tetrahydro-4-methyl-2-(2-methylpropyl)-2H-pyran-4-ol

SMILES: CC(C)C[C@H]1C[C@](C)(O)CCO1

Chemistry, Properties & Perfumer Guide

The Chemistry

trans-Tetrahydro-2-isobutyl-4-methylpyran-4-ol belongs to the pyran derivatives class, synthetic molecules designed to mimic natural woody notes. It’s produced through catalytic hydrogenation of appropriate precursors, followed by purification to isolate the desired stereoisomer. The trans configuration of the isobutyl group is crucial for its odor characteristics, demonstrating how subtle structural changes can dramatically affect scent profiles in fragrance chemistry.

Physical & Chemical Properties

AppearanceColorless to pale yellow liquid
Boiling PointData not available
DensityData not available
Refractive IndexData not available

Perfumer Guide

Note Position
Heart to Base
Volatility
Medium (2-4 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance1-3%Up to 5%Used as woody modifier
Functional Fragrance0.1-0.5%Up to 1%For subtle woody depth

Classic Accords

Tip: Use with ionones to create a smooth woody-floral accord with excellent diffusion.

Alternatives & Comparisons

1
Sandalore CAS 65113-99-7

A more intense sandalwood substitute with better substantivity when stronger woody character is needed.

2
Ebanol CAS 14528-94-2

For situations requiring a cleaner, more pronounced woody note without floral facets.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. Consult current IFRA Standards Library before formulating.

IFRA Status

No specific IFRA restrictions. General usage guidelines apply.

RIFM Assessment

Under evaluation by RIFM. Preliminary data suggests acceptable safety profile at current usage levels.

Sustainability

As a synthetic material, this ingredient avoids the sustainability challenges of natural sandalwood sourcing. However, its production requires petrochemical feedstocks and energy-intensive processes. The fragrance industry is investigating greener synthesis routes to reduce environmental impact while maintaining the desirable olfactory properties.

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References

    Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.

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    Physicochemical Properties

    DTXSID: DTXSID101534881

    Physical Properties

    Molecular Weight 172.268 g/mol🔬 EPA CompTox

    Partition & Solubility

    LogP (Octanol-Water) 1.962 dimensionless💻 Computed

    Molecular Descriptors

    Topological Polar Surface Area 29.46 Ų💻 Computed
    H-Bond Donors 1 count💻 Computed
    H-Bond Acceptors 2 count💻 Computed
    Rotatable Bonds 2 count💻 Computed
    Aromatic Rings 0 count💻 Computed

    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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