Monday, February 16, 2015


Common name: Letrozole; Letrozol; Femara
Trademarks:  Femara
Molecular Formula: C17H11N5 
CAS Registry Number: 112809-51-5
CAS Name: 4-[(4-cyanophenyl)(1H-1,2,4-triazol-1-yl)methyl]benzonitrile
Molecular Weight: 285.302
InChI: InChI=1S/C17H11N5/c18-9-13-1-5-15(6-2-13)17(22-12-20-11-21-22)16-7-3-14(10-19)4-8-16/h1-8,11-12,17H
Activity: Antineoplastic Agents, Hormonal Therapy; Aromatase Inhibitors; Breast Cancer Therapy; Post Surgery Therapy; Estrogen Therapy; Fertility Treatment;  For Ovarian Stimulation; Termination of Pregnancy
Status: Launched 1995
Originator: Novartis AG

Letrozole synthesis: US4978672A (also Ref. 2)

1. Bowman, R. M.; et. al. Aromatase inhibitors. US4978672A
2. Prous, J.; et. al. Letrozole. Drug Fut 1994, 19, 335-337.
3. Dellapasqua, S.; et. al. Expert Opin Drug Metab Toxicol 2010, 6(2), 251-259. (activity)
4. Mouridsen, H.; et. al. Superior efficacy of letrozole versus tamoxifen as first-line therapy for postmenopausal women with advanced breast cancer: results of a phase III study of the International Letrozole Breast Cancer Group. J Clin Oncol 2001, 19(10), 2596-2606. (activity)
5. Haynes, B. P.; et. al. The pharmacology of letrozole. J Steroid Biochem Mol Biol 2003, 87(1), 35-45. (activity)