Letrozole

Description

Letrozole · CAS 112809-51-5 · C17H11N5. UNII 7LKK855W8I. Melting Point: 184-185 °C; Melting Point: 181-183 °C; Melting Point: 184 - 185 °C.

Identification

CAS Registry Number	112809-51-5
PubChem CID	3902
Molecular formula	C17H11N5
IUPAC name	4-[(4-cyanophenyl)-(1,2,4-triazol-1-yl)methyl]benzonitrile
UNII (FDA)	7LKK855W8I

Computed Descriptors

Molecular Weight	285.30
XLogP3	2.7
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	3
Exact Mass	285.10144537
Monoisotopic Mass	285.10144537
Topological Polar Surface Area	78.3
Heavy Atom Count	22
Formal Charge	0

Physical & Chemical Properties

Melting Point	184-185 °C
Melting Point	181-183 °C
Melting Point	184 - 185 °C
Solubility	7.99e-02 g/L
LogP	2.5
LogP	1.84

Physical description & handling notes

• Solid
• White to yellowish crystalline powder
• Practically odorless
• Freely soluble in dichloromethane; slightly soluble in ethanol; practically insoluble in water
• 166.5 Ų [M-H]- [CCS Type: DT; Buffer gas: N2; Ionization: ESI-; Dataset: TOXCAST; Source Identifier: DTXSID4023202]
• Femara

GHS Hazard Classification

Reported hazard statements	H315 (29.5%), H319 (29.5%), H351 (15.9%), H360 (88.6%), H373 (63.6%)

Documented Uses

• Use (kg; approx.) in Germany (2009): >25
• Consumption (g per capita; approx.) in Germany (2009): 0.000305
• For the extended adjuvant treatment of early breast cancer in postmenopausal women who have received 5 years of adjuvant tamoxifen therapy. Also for first-line treatment of postmenopausal women with hormone receptor positive or hormone receptor unknown locally advanced or metastatic breast cancer. Also indicated for the treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy.
• Letrozole is indicated to treat postmenopausal women with hormone receptor (HR) positive early breast cancer, postmenopausal women with early breast cancer who have periviously been treated with tamoxifen, and postmenopausal women with HR+ or unknown advanced breast cancer. Letrozole, given with ribociclib, is indicated to treat pre, peri, and postmenopausal women with HR+ and human epidermal growth factor 2 (HER2) negative advanced or metastatic breast cancer.
• Letrozole is a nonsteroidal inhibitor of aromatase which effectively blocks estrogen synthesis in postmenopausal women and is used as therapy of estrogen receptor positive breast cancer, usually after resection and after failure of tamoxifen. Letrozole has been associated with a low rate of serum enzyme elevations during therapy and rare instances of clinically apparent liver injury.
• Breast Feeding; Lactation; Milk, Human; Antineoplastic Agents; Aromatase Inhibitors

Synonyms

letrozole; 112809-51-5; Femara; Letrozol; CGS 20267; CGS-20267; 4-[(4-cyanophenyl)-(1,2,4-triazol-1-yl)methyl]benzonitrile; Benzonitrile, 4,4'-(1H-1,2,4-triazol-1-ylmethylene)bis-; DTXSID4023202; 4,4'-(1H-1,2,4-Triazol-1-ylmethylene)dibenzonitrile; CGS20267; NSC-759652; 7LKK855W8I; 4-[(4-CYANOPHENYL)(1H-1,2,4-TRIAZOL-1-YL)METHYL]BENZONITRILE; CHEBI:6413; DTXCID503202

Frequently Asked Questions

What are the CAS number and molecular formula of Letrozole?

CAS 112809-51-5; molecular formula C17H11N5; molecular weight — g/mol.

What other names is Letrozole known by?

letrozole, 112809-51-5, Femara, Letrozol, CGS 20267, CGS-20267.

Is Letrozole classified as hazardous?

Hazard statements reported: H315, H319, H351, H360, H373.

What are the key physical properties of Letrozole?

Melting Point: 184-185 °C; Melting Point: 181-183 °C; Melting Point: 184 - 185 °C; Solubility: 7.99e-02 g/L.

Facts on this page are taken from PubChem (US National Library of Medicine) and Wikidata. Grade-specific data — assay, moisture, particle size, packaging, shelf life — is issued per batch on the COA and is not published here.