5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl- (CAS 1392325-86-8) — Woody Base Note Fragrance Ingredient

Woody · Musky

5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl-

CAS 1392325-86-8

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

What Is 5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl-?

This synthetic fragrance ingredient is a specialized molecule used in modern perfumery to create unique olfactory effects. It’s found in niche and avant-garde fragrances where perfumers seek unconventional scent profiles. As a synthetic compound, it allows perfumers to achieve effects that can’t be replicated with natural materials alone, contributing to innovative scent compositions.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
Used in regulated fragrance compositions
Limited safety data available
CAS
1392325-86-8
Formula
Mixture
MW
Variable
Odor Family
Woody · Musky
Layer 1 · Enthusiast

What Does 5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl- Smell Like?

This synthetic molecule offers a complex olfactory profile that evolves significantly over time. Initially presenting with sharp, almost metallic top notes, it quickly transitions into a heart characterized by woody-amber nuances with subtle animalic undertones. The dry-down reveals a persistent base of warm, musky tones with a faintly powdery finish. Its behavior on skin is particularly interesting, as it seems to interact strongly with body chemistry, creating personalized scent experiences.

Scent Profile
Layer 2

2D Molecular Structure

5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl-

SMILES: CC1C(C)(C)C2CCC3=CN=CN=C3C2C1(C)C

Chemistry, Properties & Perfumer Guide

The Chemistry

5H-Cyclopenta[h]quinazoline derivatives represent a specialized class of synthetic fragrance ingredients with complex polycyclic structures. The pentamethyl substitution pattern on this particular derivative contributes to its unique olfactory properties and stability. While specific synthesis routes are proprietary, these compounds are typically prepared through multi-step organic transformations involving cyclization and methylation reactions. The rigid polycyclic framework likely contributes to the material’s persistence and diffusion characteristics in fragrance applications.

Physical & Chemical Properties

Perfumer Guide

Note Position
Base
Volatility
Low (8+ hours)
Blending
Moderate
ApplicationTypical %RangeNotes
Fine Fragrance0.1-0.5%Up to 1%Used as a modifier in complex accords
Functional Fragrance0.01-0.1%Up to 0.3%Used sparingly for effect

Classic Accords

Tip: Use in trace amounts to add depth and complexity to woody-amber bases.

Alternatives & Comparisons

1
Ambroxan CAS 6790-58-5

A more widely used woody-amber material with better characterized safety profile and similar persistence.

2
Cashmeran CAS 33704-61-9

Provides some similar musky-woody aspects but with more predictable performance.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No specific IFRA restrictions currently apply to this material.

RIFM Assessment

No RIFM assessment currently available for this material.

Sustainability

As a synthetic material, this compound is produced through controlled chemical processes without direct impact on natural resources. However, the environmental footprint depends on the specific synthesis route and raw material sourcing. Being a relatively new material, full lifecycle assessments may not yet be available.

Explore 5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl-

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References

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

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    Physicochemical Properties

    DTXSID: DTXSID50889165

    Physical Properties

    Molecular Weight 244.382 g/mol🔬 EPA CompTox
    Density 0.001 g/cm^3🔬 EPA CTX
    Boiling Point 339 °C🔬 EPA CTX
    Melting Point 64.304 °C📊 OPERA
    Flash Point 168 °C🔬 EPA CTX
    Refractive Index 1.499 Dimensionless📊 OPERA
    Molar Volume 253.765 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 4.798 Log10 unitless📊 OPERA
    LogD (pH 5.5) 4.773 Log10 unitless📊 OPERA
    LogD (pH 7.4) 4.798 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 8.41 Log10 unitless📊 OPERA
    Water Solubility 0 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0 mmHg🔬 EPA CTX
    Surface Tension 34.3 dyn/cm📊 OPERA
    Thermal Conductivity 108.176 mW/(m*K)📊 OPERA

    Molecular Descriptors

    Topological Polar Surface Area 25.78 Ų💻 Computed
    H-Bond Donors 0 count💻 Computed
    H-Bond Acceptors 2 count💻 Computed
    Rotatable Bonds 0 count💻 Computed
    Aromatic Rings 1 count💻 Computed
    Molar Refractivity 74.46 cm^3/mol📊 OPERA
    Polarizability 29.518 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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