Multicomponent reaction 2 Ugi reaction 2 article chemical reaction 2 drug synthesis stereochemistry unclassified drug 17 carboxaldehyde 1 2,5 diketopiperazine derivative 1 2,5-Diketopiperazines 1 4 (2' (1h benzo[b]azol 3 yl)ethyl) 5 n cyclohexylcarboxamido 4 aza 5alpha cholestan 3 one 1 4 (2' (1h benzo[b]azol 3 yl)ethyl) 5 n cyclohexylcarboxamido 4 aza 5beta cholestan 3 one 1 4 (2' phenylethyl) 5 n cyclohexylcarboxamido 4 aza 5alpha cholestan 3 one 1 4 (2' phenylethyl) 5 n cyclohexylcarboxamido 4 aza 5beta cholestan 3 one 1 4 (3' azidopropyl) 5 n (ethoxycarbonylmethylen)carboxamido 4 aza 5alpha cholestan 3 one 1 4 (3' azidopropyl) 5 n (ethoxycarbonylmethylen)carboxamido 4 aza 5beta cholestan 3 one 1 4 benzyl 5 n (diethoxyphosphorylmethylen)carboxamido 4 aza 5alpha cholestan 3 one 1 4 benzyl 5 n (diethoxyphosphorylmethylen)carboxamido 4 aza 5beta cholestan 3 one 1 4 benzyl 5 n (methoxycarbonylmethylen)carboxamido 4 aza 5alpha cholestan 3 one 1 4 benzyl 5 n (methoxycarbonylmethylen)carboxamido 4 aza 5beta cholestan 3 one 1 4 benzyl 5 n cyclohexylcarboxamido 4 aza 5alpha cholestan 3 one 1 4 benzyl 5 n cyclohexylcarboxamido 4 aza 5beta cholestan 3 one 1 4 butyl 5 n cyclohexylcarboxamido 4 aza 5alpha cholestan 3 one 1 4 butyl 5 n cyclohexylcarboxamido 4 aza 5beta cholestan 3 one 1 4 propargyl 5 n (ethoxycarbonylmethylen)carboxamido 4 aza 5alpha cholestan 3 one 1 4 propargyl 5 n (ethoxycarbonylmethylen)carboxamido 4 aza 5beta cholestan 3 one 1 4-Azacholestanes 1 Azasteroids 1 Azasterols 1 Heterocyclic steroids 1