Synthesis of new steroidal oxazoles and thiazoles

The reaction of 5α-bromocholestan-6-one 1, its 3β-acetoxy 2 and 3β-chloro 3 analogues with urea and thiourea, separately, in ethanol under reflux affords 2'-amino-5α-cholest-6-eno [6,5-d] oxazole 4, 3β-acetoxy-2'-amino-5α-cholest-6-eno [6,5-d] oxazole 5, 3β-chloro-2'-amino-5α-cholest-6-eno [6,5-d] oxazole 6, 2'-amino-5α-cholest-6-eno [6,5-d] thiazole 7, 3β-acetoxy-2'-amino-5α-cholest-6-eno [6,5-d] thiazole 8, 3β-chloro-2'-amino-5α-cholest-6-eno [6,5-d] thiazole 9, respectively. The structures of the products have been established on the basis of their chemical, analytical and spectral analysis.