𝔖 Bobbio Scriptorium
✦   LIBER   ✦

NMR of Enaminones Part 3—1H, 13C and 17O NMR Spectroscopic Studies of Acyclic and Cyclic N-Aryl Enaminones: Substituent Effects and Intramolecular Hydrogen Bonding

✍ Scribed by Jin-Cong Zhuo

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
303 KB
Volume
35
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

17O, 13C and 1H NMR spectra for paraand meta-substituted 4-arylaminopent-3-en-2-ones (acyclic enaminones, 1 and 2) and 3-arylaminocyclohex-2-en-1-ones (cyclic enaminones, 3 and 4) are reported. The 17O, 13C and 1H shift values of these enaminones correlate well with and constants in the correlations for meta and para r m 0 r p derivatives, and with values of the corresponding anilines. Dual substituent parameters analyses were also pK a performed. Correlations of 17O and 13C chemical shifts of the carbonyl groups with those of the corresponding N-acylanilines indicate that the enaminone moiety as a whole has electronic properties similar to those of the RCONH group. The 17O shift values of the carbonyl O atoms of enaminones correlate well with their 1H and 13C data. Shieldings of 33-45 ppm for O atoms are observed for 1 and 2 compared with 3 and 4, respectively. This is attributed to intramolecular hydrogen bonding.

📜 SIMILAR VOLUMES

NMR of enaminones. Part 8—1H, 13C and 17
NMR of enaminones. Part 8—1H, 13C and 17O NMR spectra of primary and secondary 1,2-disubstituted enaminones: configuration, conformation and intramolecular hdydrogen bonding
✍ Jin-Cong Zhuo 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 269 KB

The 1H, 13C and 17O NMR spectra for four series of C-2-substituted enaminones are reported : MeCO(Me)CxCHNHR (1), EtCO(Me)xCHNHR (2), PhCO(Me)CxCHNHR (3) and MeCO(Me)CxCHNHR (4). The 1H, 13C and 17O NMR data for these enaminones show that 1 and 2 exist as mixtures of E-and Z-forms, 3 exists mainly i

1H, 13C and 17O NMR study of substituent
1H, 13C and 17O NMR study of substituent effects in 4-substituted phenylthiol esters
✍ Subbu Perumal; Gnanasambandam Vasuki; Veerappan Vijayabaskar; Sangavanaicker Sel 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 200 KB 👁 1 views

The 1H and 13C NMR spectra of 4-substituted phenylthiol acetates, benzoates and cinnamates and the 17O NMR spectra of a few thiol acetates were measured. The 13C chemical shifts of C-1 of the thiol esters when correlated with appropriate substituent-induced chemical shifts (SCS) of monosubstituted b

Spectroscopic investigations on butadien
Spectroscopic investigations on butadiene derivatives. 1H, 13C and 15N NMR studies on the π-electron distribution and intramolecular mobility of aminobuta-1,3-dienes
✍ Manfred Michalik; Thomas Freier; Kerstin Zahn; Klaus Peseke 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 333 KB 👁 2 views

The 1H, 13C and 15N NMR spectra of a series of 5-alkylthio-3-aryl-2-cyano-5-dialkylaminopenta-2,4-dienenitriles (4 and 5) with di †erent amino and aryl substituents were recorded. The NMR chemical shifts are correlated with electronic e †ects of the substituents on the donor side of the butadiene sy