𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Empirically predicted 13C NMR chemical shifts for 8-hydroxyflavone starting from 7,8,4′-trihydroxyflavone and from 7,8-dihydroxyflavone

✍ Scribed by Raymond E. March; Darcy C. Burns; David A. Ellis

Book ID
102528704
Publisher
John Wiley and Sons
Year
2008
Tongue
English
Weight
70 KB
Volume
46
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

8‐Hydroxyflavone is not found in nature. While the ^13^C chemical shifts of 8‐hydroxyflavone have been reported previously, the observed ^13^C chemical shifts were not assigned. A previously reported empirical predictive tool has been applied in reverse in order to deconvolute the ^13^C chemical shifts for 8‐hydroxyflavone from each of those of 7,8,4′‐trihydroxyflavone and 7,8‐dihydroxyflavone together with those of 7‐hydroxyflavone, 4′‐hydroxyflavone, and flavone. The two sets of calculated ^13^C chemical shifts for 8‐hydroxyflavone are in good agreement with each other in that the average absolute difference is 0.4 ppm. The previously reported but unassigned ^13^C chemical shifts for 8‐hydroxyflavone have been assigned by matching them with the averages of the two sets of calculated ^13^C chemical shifts for 8‐hydroxyflavone such that the minimum average absolute difference is 0.63 ppm. The assigned ^13^C chemical shifts of 8‐hydroxyflavone may be used, along with the ^13^C chemical shifts of the remaining monohydroxyflavones, as part of a predictive tool to rapidly assess the ^13^C NMR spectra of C8‐hydroxylated flavonoids. Copyright © 2008 John Wiley & Sons, Ltd.

📜 SIMILAR VOLUMES

Structure determination by 1H and 13C NM
Structure determination by 1H and 13C NMR of a new flavan isolated from Brosimum acutifolium: 4′,7-dihydroxy-8-prenylflavan
✍ Ana Frazão Teixeira; Antônio Flávio de Carvalho Alcântara; Dorila Piló-Veloso 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 59 KB 👁 2 views

A new flavan, identified as 4 0 ,7-dihydroxy-8-prenylflavan, was isolated from the ethanolic extract of the stem bark of Brosimum acutifolium. Its structure was elucidated by NMR methods.

Novel conformationally-constrained ?-pep
Novel conformationally-constrained ?-peptides characterized by 1H NMR chemical shiftsElectronic supplementary information (ESI) available: experimental procedures and spectral data for 1?7; xyz-coordinates, relative energies, 1H NMR chemical shifts, and H?H distances from NOESY experiments and DFT calculations for 6 and 7/8; computational methodology details. See http://www.rsc.org/suppdata/cc/b3/b309584c/
✍ Doerksen, Robert J.; Chen, Bin; Yuan, Jing; Winkler, Jeffrey D.; Klein, Michael 📂 Article 📅 2003 🏛 Royal Society of Chemistry 🌐 English ⚖ 236 KB
Electrophilic and oxidative chemistry of
Electrophilic and oxidative chemistry of pyrene and its non-alternant isomers: theoretical (DFT, GIAO-NMR, NICS) study of protonation carbocations and oxidation dications from pyrene, azupyrene (dicyclopenta[ef,kl]heptalene) and dicyclohepta[ed,gh]pentaleneElectronic supplementary information (ESI) available: Table S1: Electronic energies (E), zero point energies (ZPE) and Gibbs free energies (G) obtained from DFT calculations for the studied molecules and cations at B3LYP/6-31G(d) level. Figs. S1, S8 and S10 and Tables S2?S14: Optimized structures and Cartesian coordinates for 1, 1aH+, 1bH22+, 12+, 2, 2aH+, 2aH22+, 22+, 3, 3cH+, 3eH22+ and 32+. Figs. S2, S3 and S4: Computed 13C NMR chemical shifts and NPA-derived charges for 1aH+, 122+ and 12+. Fig. S5: Experimental 13C NMR chemical shifts for 1aH+ and 12+. Figs. S6, S7, and S12: HOMO?LUMO forms in the oxidation dications. Figs. S9 and S11: Bond-lengths in X-ray derived and computed structures for 2 and 3. See http://www.rsc.org/suppdata/ob/b4/b405009f/
✍ Okazaki, Takao; Laali, Kenneth K. 📂 Article 📅 2004 🏛 Royal Society of Chemistry 🌐 English ⚖ 409 KB
Booklets: Nutrition in Primary Care Seri
Booklets: Nutrition in Primary Care Series, Williams, T., L.L. Gabel, P.J. Fahey, and C.R. Gallagher-Allred, 1980. From Department of Family Medicine, 1114 University Hospitals, 456 Clinic Dr., Columbus, OH 43210, 16 self-study units: no. 1, Nutrition Content of Foods, Nutritional Supplements, and Food Fallacies; no. 2, Appraisal of Nutritional Status; no. 3, Nutrient and Drug Interactions; no. 4, Normal Diet: Age of dependency; no. 5, Normal diet: Age of parental control; no. 6, Normal Diet: Adolescence; no. 7, Normal Diet: Pregnancy and lactation; no. 8, Normal Diet: Geriatrics; no. 9, Dietary Management in Obesity; no. 10, Dietary Management in Diabetes Mellitus; no. 11, Dietary Management in Hypertension; no. 12, Dietary Management in Hyperlipidemia; no. 13, Dietary Management in Gastrointestinal Disease; no. 14, Dietary Management for Alcoholic Patients; no. 15, Nutritional Care of Deteriorating Patients; no. 16, An Office Strategy for Nutrition-Related Patient Education and Compliance; 45 min. each, $4 each
📂 Article 📅 1982 🏛 Elsevier 🌐 English ⚖ 406 KB