Title:  Allopregnane-3b,17a,21-triol-20-one 
CAS Registry Number:  516-47-2 
CAS Name:  3b,17,21-Trihydroxy-5a-pregnan-20-one 
Additional Names:  3a,17,21-trihydroxy-20-oxo-5a-pregnane;  Reichstein's substance P 
Molecular Formula:  C21H34O4 
Molecular Weight:  350.49 
Percent Composition:  C 71.96%, H 9.78%, O 18.26% 
Literature References:  Isoln from adrenal glands:  Steiger, Reichstein, Helv. Chim. Acta 21, 546 (1938); Reichstein, Gatzi, ibid. 1185.  Partial synthesis from cholesterol:  Reichstein, von Euw, ibid. 24, 401 (1941).  Prepn from allopregnan-3b-ol-20-one:  Rosenkranz et al., J. Am. Chem. Soc. 72, 4081 (1950); from 3b-acetoxy-21-bromo-17a-hydroxy-2-oxoallopregnane:  Kaufmann et al., US 2596562 (1952 to Syntex). 
Properties:  Pointed needles from abs ethanol, decomp 230-239°.  [a]D20 +48.0° (c = 0.938 in abs ethanol).  Freely sol in alcohol, acetone.  Sparingly sol in ether, water. 
Optical Rotation:  [a]D20 +48.0° (c = 0.938 in abs ethanol) 
  
Derivative Type:  3,21-Diacetate  
Molecular Formula:  C25H38O6 
Molecular Weight:  434.57 
Percent Composition:  C 69.10%, H 8.81%, O 22.09% 
Properties:  Crystals from benzene, mp 208-210°.  [a]D20 +41.5° (chloroform). 
Melting point:  mp 208-210° 
Optical Rotation:  [a]D20 +41.5° (chloroform) 
  
  
Status:  This monograph has been retired and is no longer subject to revision or update.   |