Pharmaceutical impurity

Fentanyl impurity 1

Fentanyl impurity 1 is listed in the pharmaceutical impurity collection under CAS 51281-64-2. Its represented structure has formula C13H14N2 and a calculated molecular weight of 198.27 g/mol.

2D chemical structure

Chemical identity

Catalog name: Fentanyl impurity 1
Common name: Fentanyl impurity 1
Chemical name: 1-benzyl-3,6-dihydro-2H-pyridine-4-carbonitrile
CAS: 51281-64-2
SMILES: N#CC1=CCN(Cc2ccccc2)CC1
InChI: InChI=1S/C13H14N2/c14-10-12-6-8-15(9-7-12)11-13-4-2-1-3-5-13/h1-6H,7-9,11H2
InChIKey: WXEFCWCPTMOIAH-UHFFFAOYSA-N
Associated API: Fentanyl

Record ID: A5cd062a2c05b

Computed properties

C13H14N2 Molecular formula

198.269 g/molMolecular weight

198.1157 DaMonoisotopic exact mass

27.03 Å²Topological polar surface area

2.3423 Calculated LogP (Wildman–Crippen)

60.032 cm³/molMolar refractivity (Wildman–Crippen)

2 countHydrogen-bond acceptors

0 countHydrogen-bond donors

Descriptors are calculated from the displayed SMILES. Calculated LogP is not a measured partition coefficient or a pH-specific LogD.

Molecular descriptor profile

Descriptor radar

Structural feature counts

Element composition

Radar scale: 0–100 percentile within 25,771 distinct represented structures in this release, using the midpoint rank for ties. Larger values indicate a higher descriptor rank, not greater safety or toxicity. Element counts include hydrogen and combine isotopes under each element.

Radar values and percentile reference

Descriptor	Value	Percentile
Molecular weight	198.269	17.20
Calculated LogP (Wildman–Crippen)	2.3423	49.01
Topological polar surface area	27.03	11.67
Hydrogen-bond acceptors	2	15.92
Hydrogen-bond donors	0	11.28
Rotatable bonds (strict)	2	24.16

Complete molecular descriptors

Property	Calculated value	Unit / type
Molecular formula	C13H14N2	dimensionless
Molecular weight	198.269	g/mol
Monoisotopic exact mass	198.1157	Da
Topological polar surface area	27.03	Å²
Calculated LogP (Wildman–Crippen)	2.3423	dimensionless
Molar refractivity (Wildman–Crippen)	60.032	cm³/mol
Hydrogen-bond acceptors	2	count
Hydrogen-bond donors	0	count
Rotatable bonds (strict)	2	count
Heavy atoms	15	count
Heteroatoms	2	count
Rings	2	count
Aromatic rings	1	count
Aliphatic rings	1	count
Saturated rings	0	count
Aromatic heterocycles	0	count
Aliphatic heterocycles	1	count
Saturated heterocycles	0	count
Aromatic carbocycles	1	count
Aliphatic carbocycles	0	count
Fraction of sp³ carbon atoms	0.3077	fraction
Formal charge	0	e
Disconnected components	1	count
Isotopically specified atoms	0	count
Potential atom stereocenters	0	count
Unspecified atom stereocenters	0	count
Spiro atoms	0	count
Bridgehead atoms	0	count
Labute approximate surface area	90.443	Å²
Valence electrons	76	count
Radical electrons	0	count
Bertz complexity	386.747	index
Balaban J	1.9373	index

Ring categories overlap and should not be summed. No toxicity result, PDE, HBEL or acceptable intake is inferred from these descriptors.

Toxicological services and resources for Fentanyl impurity 1

Qualification and safety assessment of Fentanyl impurity 1

Explore toxicological qualification of Fentanyl impurity 1 and ICH M7 mutagenic impurity assessment of Fentanyl impurity 1 for evaluation of this impurity in its pharmaceutical context.

Where data gaps need to be addressed, resources include read-across assessment for Fentanyl impurity 1 and acceptable intake and limit justification for Fentanyl impurity 1. The relevant approach depends on the available evidence, exposure and duration of use.

Related Altox services and technical resources

Identity sources and calculation method

Identifiers originate from the source catalogues and available public identity records. InChI and InChIKey on this page are generated from the displayed SMILES. RDKit validation checks the molecular representation; it does not independently verify every catalogue assignment.

Discuss an assessment for Fentanyl impurity 1

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