3H-Pyrazol-3-one, 4-[(1,5-dihydro-3-methyl-5-oxo-1-phenyl-4H-pyrazol-4-ylidene)methyl]-2,4-dihydro-5-methyl-2-phenyl- (CAS 4702-90-3) — Woody Middle Note Fragrance Ingredient

Woody · Musky

3H-Pyrazol-3-one, 4-[(1,5-dihydro-3-methyl-5-oxo-1-phenyl-4H-pyrazol-4-ylidene)methyl]-2,4-dihydro-5-methyl-2-phenyl-

CAS 4702-90-3

Origin
synthetic
Note
Middle
IFRA
Professional use
Data as of: Apr 2026

What Is 3H-Pyrazol-3-one, 4-[(1,5-dihydro-3-methyl-5-oxo-1-phenyl-4H-pyrazol-4-ylidene)methyl]-2,4-dihydro-5-methyl-2-phenyl-?

This synthetic compound is a specialized fragrance ingredient primarily used in professional perfumery. Consumers might encounter it in complex floral or woody fragrance compositions. Its importance lies in providing unique tonal qualities that help perfumers achieve specific olfactory effects not easily replicated with natural materials.

Safety Profile

PROFESSIONAL USE
Generally safeUse with awarenessProfessional use
Restricted usage levels
Professional handling recommended
CAS
4702-90-3
Formula
Mixture
MW
Variable
Odor Family
Woody · Musky
Layer 1 · Enthusiast

What Does 3H-Pyrazol-3-one, 4-[(1,5-dihydro-3-methyl-5-oxo-1-phenyl-4H-pyrazol-4-ylidene)methyl]-2,4-dihydro-5-methyl-2-phenyl- Smell Like?

This synthetic pyrazolone derivative presents a complex olfactory profile with initial sharp chemical notes that evolve into a warm, slightly animalic heart. The dry-down reveals subtle woody-ambery undertones with a lingering metallic edge. Its behavior resembles the sophisticated tonal qualities of high-end synthetic musks but with more pronounced structural complexity.

Scent Profile
Layer 2

2D Molecular Structure

C.I. Solvent Yellow 93

SMILES: CC1=NN(C(=O)C1C=C1C(C)=NN(C1=O)C1=CC=CC=C1)C1=CC=CC=C1

Chemistry, Properties & Perfumer Guide

The Chemistry

This compound belongs to the pyrazolone class, characterized by its fused heterocyclic structure. As a purely synthetic material, it’s produced through multi-step organic synthesis involving condensation reactions. The molecule’s planar structure and conjugated system contribute to its stability and specific olfactory characteristics. Its synthetic nature allows for precise control over purity and consistency in fragrance applications.

Physical & Chemical Properties

Perfumer Guide

Note Position
Middle
Volatility
Moderate (2-6 hours)
Blending
Specialized
ApplicationTypical %RangeNotes
Fine Fragrance0.1-0.5%Up to 1%Used as a modifier in complex accords
Functional Fragrance0.05-0.2%Up to 0.5%Restricted applications

Classic Accords

Tip: Use sparingly as a bridge note between woody and musky elements.

Alternatives & Comparisons

1
Velvione CAS 37609-25-9

For similar musky-woody effects with better safety profile

2
Ambroxan CAS 6790-58-5

Alternative woody-ambery note with different tonal qualities

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No specific IFRA restrictions currently listed.

RIFM Assessment

No published RIFM assessment currently available.

Sustainability

As a synthetic material, this compound’s environmental impact is primarily related to its manufacturing process. Being produced in controlled laboratory settings reduces ecological concerns associated with natural material harvesting. However, its complex synthesis requires multiple chemical steps with associated energy inputs.

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References

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

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    Ingredient Data Sheet

    CAS 4702-90-3

    Physical Properties

    Molecular Weight358.4 g/mol🔬 PubChem
    LogP (Octanol-Water)2.8🔬 PubChem
    Boiling Point347 °C🔬 EPA CompTox
    Vapor Pressure0 mmHg @ 25°C📊 OPERA
    Flash Point225.8 °C🔬 EPA CompTox
    log Kp (skin permeability)-2.898💻 Calculated
    SMILESCC1=NN(C(=O)C1C=C2C(=NN(C2=O)C3=CC=CC=C3)C)C4=CC=CC=C4🔬 PubChem

    Volatility & Performance

    Fragrance NoteBase💻 Calculated

    Odor & Flavor

    Functional Groupsalkenearomatic💻 RDKit
    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: DTXSID80884103

    Physical Properties

    Molecular Weight 358.401 g/mol🔬 EPA CompTox
    Density 1.32 g/cm^3🔬 EPA CTX
    Boiling Point 398.413 °C📊 OPERA
    Melting Point 183 °C🔬 EPA CTX
    Flash Point 248.549 °C📊 OPERA
    Refractive Index 1.668 Dimensionless📊 OPERA
    Molar Volume 280.302 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 5.02 Log10 unitless🔬 EPA CTX
    LogD (pH 5.5) 2.704 Log10 unitless📊 OPERA
    LogD (pH 7.4) 2.254 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 11.59 Log10 unitless📊 OPERA
    Water Solubility 0 mol/L🔬 EPA CTX
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0 mmHg📊 OPERA
    Surface Tension 51.27 dyn/cm📊 OPERA

    Molecular Descriptors

    Topological Polar Surface Area 65.34 Ų💻 Computed
    H-Bond Donors 0 count💻 Computed
    H-Bond Acceptors 4 count💻 Computed
    Rotatable Bonds 3 count💻 Computed
    Aromatic Rings 2 count💻 Computed
    Molar Refractivity 104.486 cm^3/mol📊 OPERA
    Polarizability 41.421 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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