Methoxy phenols, possibly derived from

Dielectric studies have been applied principally to the problem of deciding between several possible structures. A typical H bonded example may be taken from one of Curran s papers (467) o-methoxy-phenol (guaiacol) has two possible planar configurations whose dipole moments, as calculated by the vector addition method, are widely different (Fig. 5-3). The measured value of 2.41 d indicates that the intra-molecularly H bonded form exists in the benzene and dioxane solutions used. A large number of phenols, aniline derivatives, and other disub-stituted aromatic compounds have been studied in a similar fashion, and the wide occurrence of the ortho effect has been demonstrated. If two adjacent positions of the ring have proper substituents, a H bond will form. 

Inherently chiral derivatives can be also obtained from calix[4]arenes if three different units are incorporated in the order ABAC or if only two different phenolic units are present, provided these derivatives are fixed in conformations having no symmetry plane and center. Figure 13 gives a survey of the possibilities. For such a classification, one should keep in mind that hydroxy groups (or methoxy groups but ethoxy groups are on the borderline) can pass the annulus. Their orientation may be necessary in a description of the actual conformation of such compounds. It must not be indicated, however, if different stable stereoisomers are to be... 

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