Muclear magnetic resonance spectrum of 6-substituted 4, 6-dien-3-one steroids was examined. The olefinic protons showed an interesting shift according to the kind of substituent in the 6-position. The chemical shift of C
4-proton was approximately proportional to the magnetic shielding parameter of the substituent in the 6-position. On the other hand, chemical shift of C
7-proton was dependent on the mesomeric effect of the C
8 substituent and shifts to a higher magnetic field by the presence of an electron-donating group. In the presence of ethoxyl, methoxyl, or fluorine group in the 6-position, which effects the shift of C
7-proton to a higher magnetic field, coupling constant (J) was observed between C
7-H and C
8-H. It was concluded from the fact that the size of J of C
7-proton is parallel with the size (+Δδ) of the shift of C
7-proton to the higher magnetic field, that the above phenomenon is due not to the steric hindrance of the substituent in the 6-position but rather to the higher electron density in the sp
2 at 7-position by the +M effect of the substituent.
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