A Comparison of Infrared Frequencies of 19-Nor Steroids and Their 19-Methyl Analogues

Abstract
The infrared absorption spectra of thirteen 19-nor steroids in the C-19 series were recorded by the potassium bromide dispersal technique It was found that a shift to higher frequencies occurred for the bands that have been correlated with structures in saturated 3-hydroxysteroids, 3α, 5α shifted from 998 to 1017 cm−1, 3β, 5α from 1042 to 1060 cm−1, 3α, 5β from 1035 to 1060 cm−1, and 3β 5β from 1033 to 1055 cm−1. A band near 881 cm−1 helped identify Δ4-19-nor structures, while a similar band near 885 and/or 825 cm−1 seemed characteristic for the Δ1-19-nor compound
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