• Applied Biological Chemistry
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• v.41 no.7
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• pp.550-555
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• 1998

For fluoro-quinolone carboxylic acid derivatives, one bond carbon-fluorine coupling constants are ranged from 249 Hz to 257 Hz regardless of positions. But geminal and vicinal carbon-fluorine coupling constants vary according to positions, namely, geminal coupling constants are ranged from 6 Hz to 23 Hz, and vicinal coupling constants are ranged from 1.9 Hz to 7 Hz. In cases of proton-fluorine couplings, three bond coupling constants are ranged from 9 Hz to 10.3 Hz, and four bond coupling constants ate ranged from 6 Hz to 8.3 Hz.

• Archives of Pharmacal Research
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• v.28 no.1
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• pp.16-21
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• 2005

We wanted to elucidate the reason why the trityloxymethyl substituent in $\gamma$-trityloxymethyl-$\gamma$­butyrolactone takes a sterically unfavorable specific conformation, and so we synthesized 5-trityloxymethyldihydrofuran-3-one, 3-(trityloxymethyl)-4-butanolide and 2-trityloxymethyl- tetrahy­drofuran and we then analyzed their conformation by $^{1}H-NMR$ analysis.

• Journal of the Korean Chemical Society
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• v.18 no.3
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• pp.215-220
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• 1974

Conformations and cofigurations were studied for some ${\alpha},{\beta}$-unsaturated phenylhydrazones which have similar structures to the stucture of butenedial bistosylhydrazone, a precursor of tetrahedrane, by the analysis of their nmr spectra. The chemical shift difference between two solvents, benzene and aliphatic solvents, was applied for the assigning syn and anti structures of phenylhydrazone isomers as a convenient method. In this work, it was found that the phenylhydrazones have syn configurations and also found that the dihedral angles of $CH_a-CH_b$ are around $150^{\circ}$ at room temperature from the the interpretation of the vicinal spin-spin coupling constants. These results were discussed in concerning with their conformations.