Hydrogen-Bonding in Cyclic 2-(3-Oxo-3-phenylpropyl)-Substituted 1,3-Diketones: 17O-NMR Spectra and X-Ray Structure Determination

✍ Scribed by Jin-Cong Zhuo; Kurt Schenk

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: German
• Weight: 101 KB
• Volume: 85
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/1522-2675(200205)85:5<1276::aid-hlca1276>3.0.co;2-i

✦ Synopsis

Structures of cyclic 2-(3-oxo-3-phenylpropyl)-substituted 1,3-diketones 4a ± c were determined by 17 O-NMR spectroscopy and X-ray crystallography. In CDCl 3 solution, compounds 4a ± c form an eight-memberedring with intramolecular H-bonding between the enolic OH and the carbonyl O(11)-atom of the phenylpropyl group, as demonstrated by increased shielding of specifically labeled 4a ± c in the 17 O-NMR spectra (Dd( 17 O( )) 36 ppm). In solid state, intermolecular H-bonding was observed instead of intramolecular Hbonding, as evidenced by the X-ray crystal-structure analysis of compound 4b. Crystals of compound 4b at 293 K are monoclinic with a 11.7927 (12) ä, b 13.6230 (14) ä, c 9.8900 (10) ä, b 107.192 (2)8, and the space group is P2 1 /c with Z 4 (refinement to R 0.0557 on 2154 independent reflections).