Methallenestril
Methallenestril , also known as methallenoestril and as methallenestrol, as well as Horeau's acid, is a synthetic nonsteroidal estrogen and a derivative of allenolic acid and allenestrol that was formerly used to treat menstrual issues but is now no longer marketed. It is a seco-analogue of bisdehydrodoisynolic acid, and although methallenestril is potently estrogenic in rats, in humans it is only weakly so in comparison. Vallestril was a brand of methallenestril issued by G. D. [Searle & Company] in the 1950s. Methallenestril is taken by mouth. By the oral route, a dose of 25 mg methallenestril is approximately equivalent to 1 mg diethylstilbestrol, 4 mg dienestrol, 20 mg hexestrol, 25 mg estrone, 2.5 mg conjugated estrogens, and 0.05 mg ethinylestradiol.
Synthesis
The chemical synthesis has been described: Patent: Unavailable methods:The Grignard reaction between 2-propionyl-6-methoxynaphthalene and Ethyl 2-bromoisobutyrate occurs to give Ethyl beta-ethyl-beta-hydroxy-6-methoxy-alpha,alpha-dimethylnaphthalene-2-propionate . Dehydration of the carbinol in aqueous lye may be accompanied by saponification of the ester to give . Re-esterification with diazomethane gave. Catalytic hydrogenation of the olefin led to PC608080. Saponification of the ester completed the synthesis of Methallenestril.
An alternative method is described in the patent that relies on 2-cyano-6-methoxynaphthalene . The precusor to this is described in a Hoechst patent.