Melting points, reporting analytical data

The thermophysical properties, such as glass transition, specific heat, melting point, and the crystallization temperature of virgin polymers are by-and-large available in the literature. However, the thermal conductivity or diffusivity, especially in the molten state, is not readily available, and values reported may differ due to experimental difficulties. The density of the polymer, or more generally, the pressure-volume-temperature (PVT) diagram, is also not readily available and the data are not easily convertible to simple analytical form. Thus, simplification or approximations have to be made to obtain a solution to the problem at hand. 

The major product, des base D, formed an 0-acetyl derivative and was converted to a deoxy compound F on catalytic reduction. Des base D formed no carbonyl derivatives, but permanganate oxidation afforded a mixture of 6-(4-methoxyphenyl)piperonal and 6-(4-methoxyphenyl)-piperonylic acid, the structures of which were confirmed by unambiguous synthesis (134). It follows that des base D is 6-(4-methoxyphenyl)-piperonyl alcohol (CXXVI) (117, 136, 137). The analytical data and melting point of 0-acetyl des base D agree with those reported for des base C, and it is likely that they are identical (137). The hydrogenation product of des base D, deoxy compound F, has been identified as 4 -methoxy-3,4-methylenedioxy-6-methylbiphenyl (134). 

Only one new example of the isolation and spectral data of isomunchnones has been reported since the cases presented by Gingrich and Baum. Regitz and co-workers prepared a series of remarkably stable isomunchnones 426 (Fig. 4.135). These yellow solids can often be obtained in analytical purity and have melting points in the range of 153°-207°C. Their synthesis and 1,3-dipolar cycloaddition reactions are described in Section 4.4.3.2. 

Tables XII-25 to XIM45 represent a list of pyridinols and pyridones that have been described in the literature from 1960to 1970. A few compounds reported during 1958 and 1959 are also included. Melting points boiling points, and/or analytical data, and references are given for each compound. When the nitrogen atom is unsubstituted, the pyridinol structure has been used throughout the tables, which have been divided into the following major categories 2-, 3-, and 4-pyridinols 2-, and 4-pyridones ethers of 2-, 3-, and 4-pyridinols pyridinediols, ethers of pyridinediols, pyridinetriols and ethers of pyridinetriols.

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