article drug derivative drug structure 2 drug synthesis synthesis 2 unclassified drug 16alpha bis(carbamoyloxymethyl)methyl 3alpha hydroxy 5alpha pregnan 20 one 1 16alpha carbamoyloxyethyl 3alpha hydroxy 5alpha pregnan 20 one 1 16alpha ethyl 20 oxo 5alpha pregnane 3alpha,16b diyl dicarbamate 1 16alpha ethyl 20 oxo 5alpha pregnane 3r,16b diyl dicarbamate 1 20,20 ethylenedioxy 16r bis(methoxycarbonyl)methyl 5alpha pregnan 3alpha ol 1 21 hydroxy 11,19 oxidopregn 4 ene 3,20 dione 1 21 hydroxy 6,19 oxidopregn 4 ene 3,20 dione 1 21-hydroxy-11,19-oxidopregn-4-ene-3,20-dione 1 21-hydroxy-6,19-oxidopregn-4-ene-3,20-dione 1 21-hydroxylation 1 3alpha hydroxy 16alpha (2 hydroxyethoxy) 5alpha pregnan 20 one 1 3alpha hydroxy 16alpha (2,3 dihydroxypropoxy) 5alpha pregnan 20 one 1 3alpha hydroxy 16alpha [2 hydroxy (2 ethoxyethoxy)] 5alpha pregnan 20 one 1 3alpha hydroxy 16alpha bis(methoxycarbonyl)methyl 5alpha pregnan 20 one 1 3alpha hydroxy 16alpha methoxycarbonylmethyl 5alpha pregnan 20 one 1 3alpha hydroxy 16alpha-bis(hydroxymethyl)methyl 5alpha pregnan 20 one 1 3alpha hydroxy 5alpha pregnan 20 one 1 3alpha tert butyldimethylsilyloxy 16alpha ethyl 20,20 ethylenedioxy 5alpha pregnan 16b ol 1 3alpha tert butyldimethylsilyloxy 20,20 ethylenedioxy 16alpha bis(hydroxymethyl)methyl 5alpha pregnane 1 3beta hydroxy 16ralpha (2' hydroxyethoxy) pregn 5 en 20 one 1 3r tert butyldimethylsilyloxy 20,20 ethylenedioxy 16r bis (methoxycarbonyl)methyl 5alpha pregnane 1 4 aminobutyric acid A receptor 1 Acetylation 1 Aldosterone 1