CAS number
Beilstein Reference 2139461
Jmol-3D images Image 1
Molecular formula C20H26O2
Molar mass 298.42 g mol−1
Density 1.063g/cm3[1]
Melting point 164 °C (327 °F; 437 K)[2]
Boiling point 431.369 °C (808.464 °F; 704.519 K)
Vapor pressure 0 mmHg @ 25°C
Flash point 192.811 °C (379.060 °F; 465.961 K)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)

Benzestrol is an organic compound that was formerly used as a non-steroidal estrogen antagonist.[3] It is part of a family of compounds called DES drugs with the family leader called diethylstilbestrol. These drugs were used extensively in the mid-1900s and were finally banned by the FDA due to them causing tumors in the children of women who used them.[4]


  • Uses 1
  • History 2
  • Synthesis 3
  • References 4


Benzestrol and other DES drugs were used as a synthetic estrogen in order to prevent premature births.[4] Based on the idea that premature births happened because the mother did not produce enough estrogen on her own, doctors prescribed benzestrol to mothers in order to increase their estrogen levels. Studies have been done in the past on normal, mature and castrate female rats. Benzestrol produced the same type of estrus in the castrate rat when injected at 0.8 to 1.0 micrograms as when the rat was injected with 2.0 to 2.5 micrograms of estrone.[5] This is significant because less benzestrol could be used to produce the same effect as estrone in increasing estrogen production. It has been used in the past as a nonsteroidal estrogen antagonist.


Benzestrol is a compound in the family of DES drugs. These drugs were first produced in the late 1930s. In 1953, experiments began on benzestrol and other DES drugs to see if they actually helped stop premature births. This study in 1953 found that benzestrol did not in fact help stop premature births.[4] A study in 1971 found that benzestrol was the cause of a rare vaginal cancer in girls and women whose mothers had been on benzestrol while pregnant.[4]


Benzestrol synthesis:[6]


  1. ^ "CAS". Retrieved 15 November 2012. 
  2. ^ "Benzestrol". Retrieved 15 November 2012. 
  3. ^ "Chemical Book". Retrieved 13 November 2012. 
  4. ^ a b c d "DES History". CDC. Retrieved 2012-12-17. 
  5. ^ Stebbins, R.B.; Blanchard, E.W. (1945). "The Effects of a New Synthetic Estrogen, Benzestrol Upon the Hematopoietic System in the Rat". Endocrinology 36 (5): 305.  
  6. ^ Stuart, Alfred H. (1946). "Synthetic Estrogenic Compounds. III. Trialkyl Derivatives of 1,3-Di-(p-hydroxyphenyl)-propane. Benzestrol". Journal of the American Chemical Society 68 (5): 729–733.