Intramolecular carbon-hydrogen insertion on cupric sulfate assisted decomposition of diazomethyl ketones derived from four l-methylcycloalkanecarboxylic acids and (hexahydrophenyl)acetic, homopivalic, and enanthic acids is shown to yield mostly cyclopentanones. The yields are appreciable in the conformationally favorable cases, and insertion in the solvent cyclohexane can be avoided by the use of Freon TF as the solvent The conversion of a pimaradienic diterpene into a 14-iso-16-androstanone derivative shows the power of the new method of cyclopentanone synthesis.

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During a study of the thixotropic behavior of certain fatty materials a series of alkyl esters of substituted carbamic acids was prepared, and some of the physical properties were examined. Highly purified fatty aleohols and fatty isocyanates were reacted to give urethanes with from 8 to 22 carbon atoms in both the O‐alkyl and N‐alkyl groups. The melting points of the urethanes were dependent not only on the number of carbon atoms in the molecule but also on the symmetry of the moiety. In an homologous series the melting point increases with the number of carbon atoms. When symmetry is reached, there is a sharp increase in the melting point. After this the increase is less pronounced. The urethanes give thixotropic gels with ethyl alcohol, soybean oil, solvent‐thinned resins, and other similar materials at concentrations as low as 0.5%. In general, better‐defined crystal structure and poorer thixotropic properties were observed with an increase in symmetry.

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