Azasteroids Magnetic Resonance Spectroscopy article azasteroid 4 drug synthesis unclassified drug 13C nuclear magnetic resonance spectra 2 17a allyl 3beta acetoxy 17a aza d homoandrost 5 en 17 one 2 17a allyl 3beta methoxy 17a aza d homoandrost 5 en 17 one 2 17a benzyl 3beta acetoxy 17a aza d homoandrost 5 en 17 one 2 17a ethyl 3beta acetoxy 17a aza d homoandrost 5 en 17 one 2 17a ethyl 3beta methoxy 17a aza d homoandrost 5 en 17 one 2 17a methyl 3beta acetoxy 17a aza d homoandrost 5 en 17 one 2 17a methyl 3beta methoxy 17a aza d homoandrost 5 en 17 one 2 17a-aza-d-homoandrost-5-en-17-one derivatives 2 1H nuclear magnetic resonance spectra 2 3beta acetoxy 17a aza d homoandrost 5 en 17 one 2 3beta methoxy 17a aza d homoandrost 5 en 17 one 2 4 (2' (1h benzo[b]azol 3 yl)ethyl) 5 n cyclohexylcarboxamido 4 aza 5alpha cholestan 3 one 2 4 (2' (1h benzo[b]azol 3 yl)ethyl) 5 n cyclohexylcarboxamido 4 aza 5beta cholestan 3 one 2 4 (2' phenylethyl) 5 n cyclohexylcarboxamido 4 aza 5alpha cholestan 3 one 2 4 (2' phenylethyl) 5 n cyclohexylcarboxamido 4 aza 5beta cholestan 3 one 2 4 (3' azidopropyl) 5 n (ethoxycarbonylmethylen)carboxamido 4 aza 5alpha cholestan 3 one 2 4 (3' azidopropyl) 5 n (ethoxycarbonylmethylen)carboxamido 4 aza 5beta cholestan 3 one 2 4 benzyl 5 n (diethoxyphosphorylmethylen)carboxamido 4 aza 5alpha cholestan 3 one 2 4 benzyl 5 n (diethoxyphosphorylmethylen)carboxamido 4 aza 5beta cholestan 3 one 2 4 benzyl 5 n (methoxycarbonylmethylen)carboxamido 4 aza 5alpha cholestan 3 one 2 4 benzyl 5 n (methoxycarbonylmethylen)carboxamido 4 aza 5beta cholestan 3 one 2 4 benzyl 5 n cyclohexylcarboxamido 4 aza 5alpha cholestan 3 one 2 4 benzyl 5 n cyclohexylcarboxamido 4 aza 5beta cholestan 3 one 2