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Pharmaceutical impurity

Entecavir Impurity 43

Entecavir Impurity 43 is listed in the pharmaceutical impurity collection under CAS 10310-21-1. Its represented structure has formula C5H4ClN5 and a calculated molecular weight of 169.57 g/mol.

2D chemical structure

H 2 N N C l N N H N

Chemical identity

Catalog name
Entecavir Impurity 43
Common name
Entecavir Impurity 43
Chemical name
6-chloro-9H-purin-2-amine
CAS
10310-21-1
SMILES
Nc1nc(Cl)c2nc[nH]c2n1
InChI
InChI=1S/C5H4ClN5/c6-3-2-4(9-1-8-2)11-5(7)10-3/h1H,(H3,7,8,9,10,11)
InChIKey
RYYIULNRIVUMTQ-UHFFFAOYSA-N
Associated API
Entecavir

Record ID: A3485a4108f2a

Computed properties

C5H4ClN5 Molecular formula
169.575 g/molMolecular weight
169.0155 DaMonoisotopic exact mass
80.48 ŲTopological polar surface area
0.5885 Calculated LogP (Wildman–Crippen)
41.1061 cm³/molMolar refractivity (Wildman–Crippen)
4 countHydrogen-bond acceptors
2 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

Mol. weight LogP TPSA HBA HBD Rotatable 25 50 75 100

Structural feature counts

0 2 4 Count H-bond acceptors H-bond donors Rotatable bonds Rings Aromatic rings Stereo centers

Element composition

C Cl H N 0 2 4 Number of atoms

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
DescriptorValuePercentile
Molecular weight169.57510.08
Calculated LogP (Wildman–Crippen)0.588519.82
Topological polar surface area80.4858.21
Hydrogen-bond acceptors450.68
Hydrogen-bond donors264.87
Rotatable bonds (strict)03.45

Complete molecular descriptors

PropertyCalculated valueUnit / type
Molecular formulaC5H4ClN5dimensionless
Molecular weight169.575g/mol
Monoisotopic exact mass169.0155Da
Topological polar surface area80.48Ų
Calculated LogP (Wildman–Crippen)0.5885dimensionless
Molar refractivity (Wildman–Crippen)41.1061cm³/mol
Hydrogen-bond acceptors4count
Hydrogen-bond donors2count
Rotatable bonds (strict)0count
Heavy atoms11count
Heteroatoms6count
Rings2count
Aromatic rings2count
Aliphatic rings0count
Saturated rings0count
Aromatic heterocycles2count
Aliphatic heterocycles0count
Saturated heterocycles0count
Aromatic carbocycles0count
Aliphatic carbocycles0count
Fraction of sp³ carbon atoms0fraction
Formal charge0e
Disconnected components1count
Isotopically specified atoms0count
Potential atom stereocenters0count
Unspecified atom stereocenters0count
Spiro atoms0count
Bridgehead atoms0count
Labute approximate surface area66.6243Ų
Valence electrons56count
Radical electrons0count
Bertz complexity394.6721index
Balaban J2.9066index

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 Entecavir Impurity 43

Qualification and safety assessment of Entecavir Impurity 43

Explore toxicological qualification of Entecavir Impurity 43 and ICH M7 mutagenic impurity assessment of Entecavir Impurity 43 for evaluation of this impurity in its pharmaceutical context.

Where data gaps need to be addressed, resources include read-across assessment for Entecavir Impurity 43 and acceptable intake and limit justification for Entecavir Impurity 43. The relevant approach depends on the available evidence, exposure and duration of use.

Related Altox services and technical resources

Other catalogue designations with the same represented structure

These are separate catalogue entries; shared structure does not establish interchangeable pharmacopoeial designations.

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 Entecavir Impurity 43

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