Heretofore, as a method of producing an estrone acetal from androstane 1,4 diene 3,17 dione 17 acetal , there is, for instance, {HEAD ~ a method} as described in {TAIL ~ Japanese Patent Application Laid Open} 
as described in
Heretofore , as a method of producing an estrone acetal from androstane 1,4 diene 3,17 dione 17 acetal , there is , for instance , { HEAD ~ a method } as described in { TAIL ~ Japanese Patent Application Laid Open }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL