Substituent

About: Substituent is a research topic. Over the lifetime, 42877 publications have been published within this topic receiving 516716 citations. The topic is also known as: side chain & side group.

How Does the Electronegativity of the Substituent Dictate the Strength of the Gauche Effect

Abstract: The distinct conformational preferences observed for the pentofuranosyl moieties in various 3'-substituted 2',3'-dideoxythymidine derivatives are closely related to the strength of the 3'-gauche effect, which is directly dictated by the electronegativity of the 3'-substituent. The efficiency of the 3'-gauche effect can now be quantitatively calculated with the help of simple linear calibration curves that correlate the gauche effect enthalpy AH^^") and the group electronegativity (x) of the 3'-substituent.

Quantification and classification of substituent effects in organic chemistry: a theoretical molecular electrostatic potential study

Abstract: Substituent effects in organic chemistry are generally described in terms of experimentally derived Hammett parameters whereas a convenient theoretical tool to study these effects in π-conjugated molecular systems is molecular electrostatic potential (MESP) analysis. The present study shows that the difference between MESP at the nucleus of the para carbon of substituted benzene and a carbon atom in benzene, designated as ΔVC, is very useful to quantify and classify substituent effects. On the basis of positive and negative ΔVC values, a broad classification of around 381 substituents into electron withdrawing and donating categories is made. Each category is again sorted based on the magnitude of ΔVC into subcategories such as very strong, strong, medium, and weak electron donating/withdrawing. Furthermore, the data are used to show the transferability and additivity of substituent effects in π-conjugated organic molecules such as condensed aromatic, olefinic, acetylenic, and heterocyclic systems. The transferability properties hold good for ΔVC in all these molecular systems. The additive properties of substituent effects are strongly reflected on ΔVC and the predictive power of the data to assign the total substituent effects of multi-substituted systems is verified. The ΔVC data and the present classification of substituents are very useful to design π-conjugated organic molecular systems with desired electron rich/poor character.

Compound having s1p receptor binding potency and use thereof

Abstract: Compounds of the general formula (I); their salts, N-oxides and solvates; prodrugs thereof; and medicines comprising these. (I) [wherein each of the ring A and ring D is a substituted or unsubstituted cyclic group; each of E and G is a bonding group or a spacer whose main chain has 1 to 8 atoms; L is a hydrogen atom or substituent; X is a substituted or unsubstituted amino or substituted or unsubstituted heterocycle containing at least one nitrogen atom; and n is 0 to 3 with the proviso that when n is =2, multiple rings A may be identical with or different from each other]. The compounds of the general formula (I) have S1P receptor (especially EDG-1 and/or EDG-6) binding potency and are useful in the prevention and/or therapy for transplant rejection, autoimmune diseases, allergic disorders, etc.