Synthesis of 2-oxacortexone and its effect on Ca2+ uptake in bovine spermatozoa

Aryeh A. Frimer, Gladis Aljadeff, Sara Rubinstein, Haim Breitbart

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Low temperature base catalyzed autoxidation (BCA) of the A-ring of 21- acetoxypregn-5-ene-3,20-dione 20-athylene ketal (7) resulted in the saponification of the ester with the concomitant formation of 2,21- dihydroxypregna-1,4-diene-3,20-dione 20-ethylene ketal (8). Continued BCA at ambient temperature, converts the latter to 1,21-dihydroxy-2-oxaprogesterone 20-ethylene ketal (9), which is reduced by NaBH4 to the 2-oxasteroid, 21- hydroxy-2-oxaprogesterone 20-ethylene ketal (10). Treatment of enol 8, lactol 9, and lactone 10 with aqueous acid generates the corresponding deprotected analogs 2,21-dihydroxypregna-1,4-diene-3,20-dione (enol 11), 1,21-dihydroxy- 2-oxaprogesterone (lactol 12), and 2-oxacortexone (2- oxadesoxycorticosterone, 21-hydroxy-2-oxaprogesterone, lactone 13). In bovine spermatozoa, neither 2-oxasteroid ketal 10 nor its deprotected analog 13 stimulated Ca2+ uptake. In high concentration (0.5 mM), the inhibition of Ca2+ uptake is only 37% for 13, as compared to 83% found with the parent steroid, cortexone (desoxycorticosterone, 21-hydroxyprogesterone, 5). The difference in molecular structure between 13 and 5 indicates the importance of the oxygen atom in ring A in achieving the protective effect of the steroid. Ketalization of the C-20 carbonyl is not important for protection. Thus it seems that by replacing C-2 by an oxygen atom we can reduce the biological damage caused by relatively high concentrations of steroid treatment. These results are highly significant when treatment of patients with high doses of steroids is considered.

Original languageEnglish
Pages (from-to)117-121
Number of pages5
JournalArchiv der Pharmazie
Issue number5
StatePublished - May 1997


  • Base catalyzed autoxidation
  • Calcium uptake
  • Desoxycorticosterone
  • Oxasteroids
  • Spermatozoa


Dive into the research topics of 'Synthesis of 2-oxacortexone and its effect on Ca2+ uptake in bovine spermatozoa'. Together they form a unique fingerprint.

Cite this