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hexamethoxy-5H-tribenzo[a,d,g]cyclononene) and Related CornpoundsBy A. S. LINDSEYThe product of condensation of veratrole and formaldehyde under acid conditions is shown to be a cyclic trimer possessing a novel ring system (I; R = Me). Three general methods of preparing this compound and its analogues are examined and their trimeric nature is established. Certain aspects of the stereochemical conformation of cyclotriveratrylene are discussed.

The cyclic amido-structure of 2-pyridone, 6-methyl-Z-pyridone, 2-quinoloce, and 4-methyl-2-quinolone in the solid state and in solution has been confirmed by infrared measurements. The spectra of sodium 2-pyridyl oxide and potassium 2-quinolyl oxide have also been examined and a chelated structure for potassium 2-quinolyl oxide is suggested to explain its inertness in the Kolbe-Schmitt reaction.IT is well known that the pyridones and analogous compounds are tautomeric with respect to the keto and the enol forms. For 2-pyridone these are represented by (I) and (11) respectively, probably being stabilised by resonance with the dipolar forms (111) and (IV). ) showed by a study of the ultraviolet absorption spectra that in methanolic solution 2-ar,d 4-pyridone exist substantially in the amido-form. Addition of alkali led to marked spectral changes which were ascribed to a change towards the enol form. The spectrum of 3-hydroxypyridine, however, was not greatly affected by either alkali or acid. Leis and Curran ( J . Amer. Chem. SOC., 1945, 67, 79), on the basis of the dipole moment for a dioxan solution, concluded that in this solvent 4pyridone

Mild acid-catalysed hydration of caryophyllene oxide affords a disecondary glycol formulated as 4 : 4 : 8-trimethyltricycZo[6 : 3 : 1 : 01'5ldodecane-2 : 9diol. Similar hydration of isocaryophyllene oxide t furnishes a glycol stereoisomeric a t C,,,. These experiments prove that caryophyllene and isocaryophyllene are geometrical isomers about the endocyclic ethylenic linkage. On the basis of relative reactivities towards electrophilic reagents and by consideration of the course of isomerisation induced by nitrous acid, caryophyllene is regarded as the trans-isomer (I), and isocaryophyllene as the cis-isomer (X)On palladium-catalysed hemihydrogenation both caryophyllene and isocaryophyllene give the same (cis-) dihydro-compound.

A study has been made of the behaviour on heating of the alkali-metal mono-and di-salicylates and *-hydroxybenzoates, and of some related substances. Some rate studies are reported for these reactions.When a mixture of 14C-labelled potassium carbonate and dipotassium salicylate was heated at 200" appreciable exchange accompanied the rearrangement with formation of labelled p-hydroxybenzoate. The mechanism of these reactions is discussed DIFFERENCES in behaviour of the alkali metals in organic reactions have often been noted.2739 4 The Kolbe-Schmitt reaction provides a classical examp1e.l' 2s 59 and Ost * drew attention to the remarkable difference in behaviour between sodium and potassium salicylate at 220". The former yielded disodium salicylate, the latter dipotassium $-hydroxybenzoate. There occur in the literature many conflicting reports concerning the thermal rearrangement of the alkali-metal salts of aromatic hydroxy-carboxylic acids. In large measure, these are due to the use of carbon dioxide as a supposedly inert atmosphere in the early studies of these rearrangement^,^^ lo for under these conditions it is possible for carboxylation to intervene.More recent studies have revealed differences not only in the ratio of orthoto parasubstitution, but also in the extent of carboxylation and in the tendency to form hydroxydicarboxylic acids, particularly at higher temperatures.6311 In the Marasse procedure also differences have been observed 11, I29l3 and these distinctions hold in the phenol, naphthol, and heterocyclic series.6In order to establish how far purely thermal rearrangements are involved in the Kolbe-Schmitt reaction, a study of the behaviour on heating of various alkali-metal derivatives of salicylic acid and other aromatic hydroxy-carboxylic acids was undertaken.Most of our experiments were conducted in vacuo; this served to minimise oxidation, and in those cases where carbon dioxide was evolved eliminated the possibility of recarboxylation. From our studies on the monoalkali-metal salts the following facts have emerged. Monosodium salicylate at 300" yields equimolecular amounts of phenol, carbon dioxide, and disodium salicylate. A mixture of sodium phenoxide and monosodium salicylate at 140" gives equimolecular amounts of free phenol and disodium salicylate.In 1875 Kolbe

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