128607-22-7

In February 2013, the US FDA approved ospemifene (also referred to as FC1271a), for the treatment ofmoderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy (VVA), due tomenopause. It is estimated that there are 150 million postmenopausal women worldwide with 40–70% suffering from VVA. Ospemifene is a selective estrogen receptor (ER) modulator (SERM) and the first nonhormonal, nonestrogen for the treatment of moderate to severe dyspareunia in women with menopausal VVA. It binds to ERα (IC₅₀～800 nM) and ERβ (IC₅₀～1600 nM) with tissue-specific estrogenic agonist/antagonist effects. Treatment with ospemifene increases the thickness of the vaginal tissue thereby decreasing fragility of the tissue and reducing potential for pain during sexual intercourse.

Tess Diagnostics and Pharmaceuticals/Hormos Medical/QuatRx (Finland)

Treatment of vaginal atrophy, osteoporosis, and vasomotor symptoms.

ChEBI: An organochlorine compound that is a selective estrogen receptor modulator; used for treatment of dyspareunia.

Osphena

Ospemifene is a SERM that is currently in Phase II/III clinical trials for the treatment of postmenopausal osteoporosis and urogenital atrophy. It is a known metabolite of toremifene, a triphenylethylene derivative used to treat breast cancer.Ospemifene has been shown to have beneficial effects on the bone without significant estrogen-related side effects. The beneficial effect observed on bone stems from this agent's ability to increase osteoblast proliferation and, as a result, to enhance bone mineralization as well as bone formation. Unlike tamoxifen, ospemifene does not induce osteocyte apoptosis.

The drug can be synthesized succinctly in two steps. First, alkylation of commercially available 4-hydroxybenzophenone (130) with ethylene carbonate and catalytic sodium iodide in refluxing toluene provided benzophenone 131 in 94% yield. This was followed by a McMurry coupling involving benzophenone 131 with chloropropiophenone 132 in the presence of zinc powder and titanium tetrachloride in 2-methyltetrahydrofuran. This reaction gave rise to a mixture of triphenylethylenes directly as a 5.5:1 ratio of Z to E isomers which could be separated by crystallization in aqueous methanol to give a mixture of olefins, 98% of which was comprised of the desired Z-isomer corresponding to ospemifene (XVII). The product purity was further improved by recrystallization to give 99.9% of the Z-isomer in 46% yield from 131. Thus, ospemifene was synthesized in two steps and 43% overall yield.

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