Study of substituent effects on intramolecular hydrogen bonding of (5Z)-7-[(1R,2R,3S,5S)-2-(4-substituted benzoylamino)-6,6-dimethylbicyclo[3.1.1]hept-3-yl]hept-5-enoic acids and their esters in dilute CCl4 solution by FTIR spectroscopy

2003 ◽  
Vol 32 (2) ◽  
pp. 249-259 ◽  
Author(s):  
Mamoru Takasuka ◽  
Tsunetoshi Honma ◽  
Takashi Saito
1972 ◽  
Vol 27 (6) ◽  
pp. 663-674 ◽  
Author(s):  
Gotthard H. Krause ◽  
Herbert Hoyer

The change of free enthalpy involved in intramolecular hydrogen bonding is smaller if the proton acceptor group can rotate round a single bond, as compared to proton acceptor groups which are fixed in a position optimal for hydrogen bonding. Also, the free enthalpy change is altered when the rotation of the proton acceptor is sterically restricted. This is demonstrated by comparing the absorptions of carbonyl stretching vibrations in the infrared spectra of certain compounds showing rotational isomerism. In the present study derivatives of 5-hydroxy-2,2-dimethyl-6-carbomethoxychromanone- (4), 3-nitrosalicylaldehyde and 3-nitro-2-hydroxy-acetophenones substituted in the position 5 and 6 are examined.


1966 ◽  
Vol 44 (11) ◽  
pp. 1261-1269 ◽  
Author(s):  
G. E. Dunn ◽  
Fei-lin Kung

Ionization constants at 25 °C have been determined by a spectrophotometric method for 17 substituted salicylic acids. These have been fitted to the simple Hammett relationship and to the extended one proposed by Jaffe, which takes into account the transmission of substituent effects by the o-hydroxy group. The results with Jaffe's equation show that substituent effects on acidity are transmitted only slightly, if at all, through the intramolecular hydrogen bond of a chelate ring. Possible interpretations of the results are discussed.


2004 ◽  
Vol 69 (6) ◽  
pp. 1866-1871 ◽  
Author(s):  
Chia-Hui Chien ◽  
Man-kit Leung ◽  
Jen-Kuan Su ◽  
Gene-Hsiang Li ◽  
Yi-Hung Liu ◽  
...  

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