peri-Interactions are important in determining both the conformation of the dihydropyran ring of 2-benzopyrans as well as the stereochemistry of its substituents.
The preferred half-chair conformation of ring A in 5(10)-estrenes
✍ Scribed by Samuel G. Levine; Dorothy M. Feigl; Nancy H. Eudy
- Publisher
- Elsevier Science
- Year
- 1967
- Tongue
- French
- Weight
- 240 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
We have previously (2) described an unusual type of conformational preference effect vhich vaa found to operate in ring A of some 3-substituted (-OH and -N3), A 5(10) -steroids. From the RMR spectra of these epimer pairs in the C-3 proton region, It was evident that the 3a-and
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The preferred conformations of C"-methyl phenylglycine, C"-methyl phenylalanine, and C"-methyl homophenylalanine residues, as determined in model peptides (including homopeptides) by Fourier transform ir absorption, 'H-nmr, CD, and x-ray diffraction techniques, are compared with the aim of investiga
## Abstract The conformations of (__Z__)‐ and (__E__)‐5‐oxo‐__B__‐nor‐5,10‐secocholest‐1(10)‐en‐3__β__‐yl acetates (2 and 3, resp.) were examined by a combination of X‐ray crystallographic analysis and NMR spectroscopy, with emphasis on the geometry of the cyclononenone moiety. The ^1^H‐ and ^13^C‐