Triphenylbromoethylene

A diethoxylated derivative of triphenylbromoethylene, estrobin (DBE), is also an estrogen, but, in contrast, was never marketed. An ethylated derivative of triphenylbromoethylene, broparestrol (BDPE), is a selective estrogen receptor modulator (SERM) that has been marketed. Although the vinylic halogens has already been discussed, it was discovered that Triphenylacrylonitrile [6304-33-2] also potently modulates the estrogen receptor. ==Synthesis and reactions==

The synthesis of triphenylbromoethylene has been discussed previously: Grignard reaction of Triphenylbromoethylene with carbon dioxide gives a compound that is called Triphenylacrylic acid [4452-05-5]. The acid can then undergo esterification with Diethylethanolamine [100-37-8] (via the acid chloride for example would work). This agent was claimed to have hormonal activity but was also stated to function as a coronary vasodilator. In terms of the SAR it is counselled to consider an agent that is called Cinnamaverine [1679-75-0]. Cinnamaverine has the same structure as the compound just described but differs in that it was made by the esterification of 2,3-diphenylacrylic acid [91-48-5]. By contrast though, Cinnamaverine was claimed to function as a Local anaesthetic, antispasmodic agent. It does need to be said though that saponification of Triphenylacrylonitrile [6304-33-2] would also yield the Triphenylacrylic acid. It is worth pointing out that this compound was made by a reaction that is called a Knoevenagel condensation. (The related Perkin reaction only works with benzaldehydes and not benzophenones.) == See also ==