Synthesis of substituted steroidal thiadiazole, triazole and oxidotriazole

Abstract

Ethyl-5-cholesten-3β-O-acetate 2 and its thiosemicarbazide 3 have been synthesized by the reaction of 3β-hydroxycholest-5-ene 1 with ethyl chloroacetate and 2 with thiosemicarbazide in 1,4 dioxane, respectively. The thiosemicarbazide 3 on chemoselective heterocyclization with conc. H₂SO₄, conc. NaOH and iodine in the presence of alkali separately afforded 3β-[5'-amino-1',2',4'-thiadiazole-3'-methoxy]-cholest-5-ene 4,3β-[5'-mercapto-1',2',4'-triazole-3'-methoxy]-cholest-5-ene 5 and 3β-[5'-mercapto-3',5'-oxido-1',2',4'-triazolo-3'-methoxy]-5⍺-cholestane 6, respectively. The structures of these compounds have been established on the basis of elemental, analytical and spectral data.