Carbonyl stretching frequencies and transmission of electronic effects in 1-phenyl-3-(5-aryl-2-furyl)propenones and 1-phenyl-3-(5-aryl-2-thienyl)propenones

Abstract

The s-cis and s-trans carbonyl stretching frequencies of a series of fraras-l-phenyl-3-(5-aryl-2-furyl )propenones (I) and ¿raras-l-phenyl-3-(5-aryl-2-thienyl)propenones (II) have been measured in carbon tetrachloride and chloroform solutions. Statistically significant linear free-energy relationships were obtained between y(C=0) and + constants; poorer correlations using values were obtained in all cases. The data were also treated using the Swain-Lupton F and R constants, and poorer correlations than noted with + were obtained. The influence of the conformation on the transmission of electronic effects is discussed and compared with that in analogous systems. The parameters of the linear free-energy relationships for series I and II were compared with those for a series of ¿raras-l-phenyl-3-arylpropenones (III). Using the slopes of y(C=0) vs. + correlations in series I-III the transmissive factors for the furan and thiophene rings were calculated and related to data published earlier. The determined order of transmission for the intervening groups was furan > thiophene > benzene.

Bond fixation in annulenes. 14. Synthesis of and bond shifting equilibrium between 1,4- and 1,6-di-tert-butylcyclooctatetraenes

“…Nonetheless, the equilibrium distribution between 4 and 5 proved unexpected. In an independent study carried out almost simultaneously, Lyttle, Streitwieser, and Kluttz also noted the same unusual features of this double bond isomerism.9 Brj HOAc Scheme I 0 KOAc HOAc 0 OAc (7) Paquette, L. A.; Gardlik, J. M.; Johnson, L. K.; McCullough, K. J. J. Am.…”

“…4-Bromo-2,4,6-tri-tert-butylcyclohexa-2,5-dien-l-one (7). To a cold (0 °C), magnetically stirred solution of 6 (32.0 g, 0.12 mol; Aldrich) in methanol (120 mL) and glacial acetic acid (120 mL) was added dropwise 24.0 g (0.152 mol) of bromine.…”

Studies of NMR Chemical Shifts of Chalcone Derivatives of Five‐membered Monoheterocycles and Determination of Aromaticity Indices

“…The presence of an enone moiety in chalcone has been the point of interest in studying the transmission of the electronic effect of the substituent from one aryl ring to the other ring. For example, the carbonyl stretching frequencies in 1‐phenyl‐3‐(5‐aryl‐2‐furyl or 2‐thienyl)propenones were studied in order to compare the effect of the heterocyclic rings in the transmission of the electronic effect . ( E )‐1‐(5‐methyl‐2‐furyl)‐3‐(substituted phenyl)‐2‐propen‐1‐ones ( 8 , 5‐CH 3 ) were synthesized by crossed‐aldol condensation between 2‐acetyl‐5‐methylfuran and substituted benzaldehydes .…”

“…For example, the carbonyl stretching frequencies in 1-phenyl-3-(5-aryl-2-furyl or 2-thienyl)propenones were studied in order to compare the effect of the heterocyclic rings in the transmission of the electronic effect. 20…”

Influence of conformation on transmission of electronic effects of substituents. Correlation of infrared carbonyl stretching frequencies of 4-substituted α-naphthyl styryl ketones

“…In recent years much attention has been paid to the influence of conformation and configuration on the transmission of electronic effects of the substituents in a,P-unsaturated ketones. [1][2][3][4][5][6][7] The a,p-unsaturated ketones exist in two different conformations namely s-cis and s-trans. The influence of conformation on the transmission of electronic effects of the substituents has been investigated by measuring the i.r.…”