Synthesis of new spiro-steroids,II: Steroid-17-spiro-oxazolidinones

New, potential aldosterone blocking 17-spiro-oxazolidinone derivatives with androstane, estrane and 13β-ethyl-gonane ring system were synthesized. 17S-Spiro-oxiranes were used as starting compounds and the oxazolidinone ring was built up in different ways. All compounds but one were devoid of considerable endocrine activities. 3-Oxo-13β-ethyl-gona- -4,9(10), 11-triene-17S-spiro-5′-(2′-oxo-3′-methyl)oxazol-idine shows significant antiandrogen activity on s.c., but none on p.o. administration.