Swain-Lupton

Table 15 contains the C chemical shifts of some selected indazoles. The major difference between indazoles and isoindazoles lies in the chemical shifts of carbons C-3 and C-7a. The substituent chemical shifW (SCS) induced by the substituent in position 3 have been discussed using an empirical model (770MR(9)716). The model that gives the best results, AS = OS + + c and 3i are the Swain-Lupton parameters and 5 is the Schaefer... 

Fujita and Nishioka have attempted to place ortho effects on the same numerical scale as meta and para effects. They assume that the normal ortho electronic effect can be represented by the standard substituent constant appropriate to the reaction (cr, cr", cr, cr°), that the steric effect is given by E , and that the proximity effect is measured by the Swain-Lupton Then a multiple LFER is written... 

RERSISTENCE TIME SWAIN-LUPTON RELATION SWAIN RELATIONSHIP... 

Yukawa and Tsuno have still another approach, also involving dual parameters Yukawa Tsuno Bull. Chem. Soc. Jpn. 1959, 32. 971. For a review and critique of this method see Shorter, in Chapman Shorter. Ref. 18. pp. 119-173, pp. 126-144. This article also discusses the Swain-Lupton and Taft oh cr approaches. For yet other approaches,... 

Correlations between substituent-induced chemical shift differences and reactivity parameters have been examined. Good linear correlations have been obtained using the Swain-Lupton two-parameter equation ... 

Hansch-Leo hydrophobic substituent parameter Hammett sigma constants Modified Swain Lupton constants... 

Table 4.5 Examples of the different electronic substitution constants used in QSAR studies. Inductive substituent constants (crO are the contribution the inductive effect makes to Hammett constants and can be used for aliphatic compounds. Taft substitution constants (cr ) refer to aliphatic substituents but use propanoic acid (the 2-methyl derivative of ethanoic acid) as the reference point. The Swain-Lupton constants represent the contributions due to the inductive (.F) and mesomeric or resonance (R) components of Hammett constants. Adapted from An Introduction to the Principles of Drug Design and Action by Smith and Williams 3rd Ed. (1998) Ed. H.J.Smith. Reproduced by permission of Harwood Academic Publishers.

To characterize the substituents (the X block) a set common substituent parameters were compiled from the literature. These parameters were as (Taft inductive parameter), trp (Hammett parameter for para substituents), F and R (Swain-Lupton dual substituent parameters), Es and Esc (Taft steric parameters), van der Waals radius, L, Bv B2, B3, (Verloop sterimol parameters), MR (molar refractivity), and n (Hansch lipophilicity parameter). Data are given in Refs. [1,19] and are not reproduced here. 

The constant values k (Table E-4) are defined according to the Swain-Lupton - field-inductive constant f, i.e. they represent the relative field effect of an atom or a group. 

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