Tetrahydro-6-(2-pentenyl)-2H-pyran-2-one (CAS 34686-71-0) — Sweet Middle Note Fragrance Ingredient

Sweet · Woody

Tetrahydro-6-(2-pentenyl)-2H-pyran-2-one

CAS 34686-71-0

Origin
synthetic
Note
Middle
IFRA
Use with awareness
Data as of: Apr 2026

What Is Tetrahydro-6-(2-pentenyl)-2H-pyran-2-one?

Tetrahydro-6-(2-pentenyl)-2H-pyran-2-one is a synthetic fragrance ingredient used in perfumery to create warm, fruity, and slightly woody notes. You might encounter it in fine fragrances, body care products, or candles where a complex, sophisticated fruitiness is desired. This molecule matters because it provides perfumers with a versatile building block that can enhance fruity accords without being overly sweet or cloying, making it valuable for modern unisex and masculine fragrances.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
Not currently IFRA restricted
Limited toxicological data available
CAS
34686-71-0
Formula
Mixture
MW
Variable
Odor Family
Sweet · Woody
Layer 1 · Enthusiast

What Does Tetrahydro-6-(2-pentenyl)-2H-pyran-2-one Smell Like?

This lactone derivative opens with a juicy, slightly green peach-like fruitiness that evolves into a creamy coconut-milk warmth. As it dries down, the scent develops a woody-amber undertone reminiscent of sun-warmed sandalwood shavings. The overall effect is a sophisticated fruity-woody hybrid with excellent diffusion—like biting into a just-ripe nectarine while standing in a cedar sauna. It has moderate tenacity, lingering as a soft skin scent for 4-6 hours.

Scent Profile
Layer 2

2D Molecular Structure

7-Decen-5-olide

SMILES: CCC=CCC1CCCC(=O)O1

Chemistry, Properties & Perfumer Guide

The Chemistry

Tetrahydro-6-(2-pentenyl)-2H-pyran-2-one belongs to the δ-lactone class, characterized by a six-membered ring with an ester functionality. While not found in nature, it’s structurally related to naturally occurring coconut lactones. Industrial synthesis typically involves the cyclization of unsaturated fatty acid derivatives or the hydrogenation of corresponding pyranones. The pentenyl side chain introduces subtle green nuances that differentiate it from simpler lactones.

Physical & Chemical Properties

Boiling PointNot available
DensityNot available

Perfumer Guide

Note Position
Middle
Volatility
Moderate (2-4 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance1-3%Up to 5%Fruity-woody modifier
Personal Care0.5-1%Up to 2%Skin-safe levels

Classic Accords

Tip: Use with ionones to create a seamless fruity-woody transition in accords.

Alternatives & Comparisons

1
δ-Decalactone CAS 705-86-2

For a more pronounced peachy-coconut character with higher tenacity.

2
γ-Dodecalactone CAS 2305-05-7

When a richer, more buttery peach note is needed.

Layer 3

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 yet evaluated by RIFM – recommended to follow general lactone safety guidelines.

Sustainability

As a synthetic material, this lactone avoids agricultural land use but requires petrochemical feedstocks. Production typically employs green chemistry principles with high atom economy. Future biotech routes using engineered yeast may offer renewable alternatives while maintaining identical olfactory properties.

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References

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

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    Ingredient Data Sheet

    CAS 34686-71-0

    Physical Properties

    Molecular Weight168.23 g/mol🔬 PubChem
    LogP (Octanol-Water)2.4🔬 PubChem
    Boiling Point238 °C🔬 EPA CompTox
    Vapor Pressure0.0229 mmHg @ 25°C📊 OPERA
    Flash Point113.1 °C🔬 EPA CompTox
    Involatility Index0.0019💻 Calculated
    log Kp (skin permeability)-2.022💻 Calculated
    SMILESCCC=CCC1CCCC(=O)O1🔬 PubChem

    Volatility & Performance

    Fragrance NoteHeart💻 Calculated
    Volatility ClassVery slow💻 Calculated
    Persistence Score2.7 / 5💻 Calculated

    Odor & Flavor

    Functional Groupsesteretheralkene💻 RDKit
    “natural product, can lead to quite remarkable Practically insoluble in water, soluble in similarity and faithful reproduction of odor. Needless to add that this method of operation Powerful oily-fruity, rather fatty and ten- may be considerably less expensive, and it acious odor with floral petal-like notes, There might encourage the perfumer in oflering a is some resemblance to the odor of refine”📖 Arctander
    Data Sources & Attribution
    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: DTXSID5051492

    Physical Properties

    Molecular Weight 168.236 g/mol🔬 EPA CompTox
    Density 0.973 g/cm^3📊 OPERA
    Boiling Point 265.539 °C📊 OPERA
    Melting Point 1.332 °C📊 OPERA
    Flash Point 118.208 °C📊 OPERA
    Refractive Index 1.463 Dimensionless📊 OPERA
    Molar Volume 174.702 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 2.229 Log10 unitless📊 OPERA
    LogD (pH 5.5) 2.229 Log10 unitless📊 OPERA
    LogD (pH 7.4) 2.229 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 5.79 Log10 unitless📊 OPERA
    Water Solubility 0.011 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.01 mmHg📊 OPERA
    Viscosity 2.574 cP📊 OPERA
    Surface Tension 30.947 dyn/cm📊 OPERA

    Molecular Descriptors

    Topological Polar Surface Area 26.3 Ų💻 Computed
    H-Bond Donors 0 count💻 Computed
    H-Bond Acceptors 2 count💻 Computed
    Rotatable Bonds 3 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 48.077 cm^3/mol📊 OPERA
    Polarizability 19.059 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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