5,7-Dihydro-2-methylthieno(3,4-d)pyrimidine (CAS 36267-71-7) — Woody Top to heart Note Fragrance Ingredient
5,7-Dihydro-2-methylthieno(3,4-d)pyrimidine
CAS 36267-71-7
What Is 5,7-Dihydro-2-methylthieno(3,4-d)pyrimidine?
5,7-Dihydro-2-methylthieno(3,4-d)pyrimidine is a synthetic fragrance compound used in niche perfumery. You’ll find it in avant-garde fragrances that push olfactory boundaries. This ingredient matters because it represents perfumery’s cutting edge – where chemistry meets artistry to create entirely new scent experiences beyond traditional natural materials.
Safety Profile
PROFESSIONAL USEWhat Does 5,7-Dihydro-2-methylthieno(3,4-d)pyrimidine Smell Like?
This synthetic molecule offers a radical departure from traditional fragrance materials – imagine the electric crackle of ozone meeting the rubbery intensity of a racing tire, with an unsettling metallic edge that lingers like the aftertaste of a lightning storm. Its piercing top notes evolve into a heart of scorched wires and industrial solvents, settling into a base that recalls hot asphalt and gunpowder residue. The dry-down leaves an unsettling yet fascinating trail of synthetic rawness that challenges conventional notions of beauty in fragrance.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as an industrial counterpoint to green notes, creating tension between nature and synthetic environments. The molecule’s rubbery facets amplify modern interpretations of classic chypre structures.
Employed here to enhance the fragrance’s notorious asphalt-like quality, adding a volatile top note that suggests freshly laid road surfaces before settling into the dark base.
2D Molecular Structure
SMILES: CC1=NC2=C(CSC2)C=N1
Chemistry, Properties & Perfumer Guide
The Chemistry
5,7-Dihydro-2-methylthieno(3,4-d)pyrimidine belongs to the thienopyrimidine class of heterocyclic compounds, featuring fused thiophene and pyrimidine rings. The molecule’s planar structure and electron-rich sulfur atom contribute to its unusual odor profile. Synthesis typically involves cyclization reactions of appropriate thiophene precursors with cyanamide derivatives under acidic conditions. The methyl group at position 2 influences volatility while the nitrogen atoms create hydrogen bonding possibilities that affect substantivity.
Physical & Chemical Properties
| Appearance | Not documented |
|---|---|
| Molecular Class | Thienopyrimidine |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Conceptual Fragrance | 0.1-0.5% | Up to 1% | Used as radical accent |
| Niche Perfumery | 0.01-0.1% | Up to 0.3% | For avant-garde effects |
Classic Accords
Tip: Use micro-doses to add unsettling modernity to otherwise conventional structures.
Alternatives & Comparisons
Offers similar rubbery/metallic facets but with more popcorn-like warmth and better blending properties for mainstream applications.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently evaluated by IFRA due to niche usage and lack of significant exposure data.
RIFM Assessment
No RIFM assessment available – consider precautionary principle in formulation.
Sustainability
As a purely synthetic material, this compound avoids natural resource depletion but requires energy-intensive synthesis. Its persistence in the environment is unknown. The small quantities used in fragrance minimize ecological impact, but responsible disposal of manufacturing byproducts is essential.
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Physicochemical Properties
DTXSID: DTXSID1052038
Physical Properties
| Molecular Weight | 152.22 g/mol🔬 EPA CompTox |
| Density | 1.201 g/cm^3📊 OPERA |
| Boiling Point | 280.5 °C🔬 EPA CTX |
| Melting Point | 64.75 °C🔬 EPA CTX |
| Flash Point | 110.526 °C📊 OPERA |
| Refractive Index | 1.631 Dimensionless📊 OPERA |
| Molar Volume | 120.725 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.649 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 1.594 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.649 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.8 Log10 unitless📊 OPERA |
| Water Solubility | 0.02 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.011 mmHg📊 OPERA |
| Surface Tension | 59.241 dyn/cm📊 OPERA |
| Thermal Conductivity | 135.567 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 25.78 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 3 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 42.985 cm^3/mol📊 OPERA |
| Polarizability | 17.041 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.
