Chemical reactivity correlation analysis

What aspects of chemical structure control the rate and mechanism by which a chemical reaction takes place Chemists have long sought good answers to this question, in terms of structure-reactivity correlations, both qualitative and quantitative. When chemists have analyzed the factors that affect reactivity, however, almost invariably the solvent has been, at first, regarded as a minor perturbation in the analysis. Unless there is some overwhelming effect, for example, the millionfold rate increase seen for some reactions such as ... 

There is a long history of efforts to find simple and interpretable /i and fi functions for various activities and properties (29, 30). The quest for predictive QSAR models started with Hammett s pioneer work to correlate molecular structures with chemical reactivities (30-32). However, the widespread applications of modern predictive QSAR and QSPR actually started with the seminal work of Hansch and coworkers on pesticides (29, 33, 34) and the developments of various powerful analysis tools, such as PLS (partial least squares) and neural networks, for multivariate analysis have fueled these widespread applications. Nowadays, numerous publications on guidelines, workflows, and... 

A major method of modeling the effect of structural variation on chemical reactivity, physical properties or biological activity of a set of substrates is the use of correlation analysis. In this method it is assumed that the effect of structural variation of a substituent X upon some chemical, physical or biological property of interest is a linear function of parameters which constitute a measure of electrical, steric, and transport effects. 

Evidence in favor of structures 1-15 for the alkaloids in this group has been furnished in Volume XI, Chapter 10, Section II. The uncertainty relating to the structure of the alkaloids nerispine, parkamine, niflexine, and amaryllidine, however, still remains. The structures of narcissidine (Volume XI, p. 331) and of the related alkaloids parkacine (p. 332) and ungiminorine (p. 333) have, on the other hand, been revised by means of X-ray analysis. Work has been devoted to the study of the physical properties of the alkaloids in this group in an attempt to establish a general relationship between structure and behavior as well as to the study of the correlation of same with other classes of alkaloids and to the investigation of the chemical reactivity of representative members. 

Correlation analysis may reveal and discriminate important factors underlying physicochemical properties, chemical reactivity, and/or biological activity. 

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