Structure elucidation of two isomeric steroids: Photolytical and thermal reaction products from norethisterone studied by two-dimensional nuclear magnetic resonance
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Two-dimensional nuclear magnetic resonance was used for the structure elucidation of two isomeric photoproducts of norethisterone, a commonly used progestogen in oral contraceptives. The predominant one of the two isolated products derived from photochemical decomposition of norethisterone upon irradiation with UV-B light (280–320 nm) was 5α,17β-dihydroxy-19-nor-17α-pregn-20-yn-3-one. The minor photoproduct appeared to be the analogous 5β-isomer,i.e.
5β,17β-dihydroxy-19-nor-17α-pregn-20-yn-3-one. The latter compound was also obtained from the thermal reduction of norethisterone-4β,5β-epoxide using aluminium amalgam in isopropanol. Two-dimensional NMR appeared to be superior to mass and IR spectrometry in identifying the isomers.
KeywordsPublic Health Aluminium Steroid Internal Medicine Nuclear Magnetic Resonance
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