We have synthesized a novel dianhydride, 2,2′‐dichloro‐4,4′,5,5′‐benzophenone tetracarboxylic dianhydride (DCBTDA). Polyimides were synthesized with DCBTDA or 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) and several relatively rigid meta‐ and para‐ substituted mononuclear diamines. The BTDA based systems were insoluble in dipolar, aprotic solvents whereas the DCBTDA based polymers displayed enhanced solubility in these solvents. The thermal stability of these polyimides was excellent as measured by 5% weight loss decomposition. The Tg's of the polymers were all above 290°C.

Sterols of a nystatin resistant mutant of the wild type parent of Saccharomyces cerevisiae were separated by a newly developed procedure involving high-pressure liquid chromatography and were identified. The mutant contained larger amounts of squalene and lanosterol (I) than the wild type, as well as 4,14-dimethylcholesta-8,24-dien-3beta-ol (II), 4,14-dimethylergosta-8,24(28)-dien-3beta-ol (III), and 14-methylergosta-8,24(28)-dien-3beta-ol (IV), which were not hitherto found in yeast. These results indicated a block in removal of the methyl group at C-14 of lanosterol. An ergosterol requiring derivative of the mutant which carried in addition a mutation in heme biosynthesis had the same sterols as the parent, but at one-third the concentration. The low level of sterols may be due to a requirement for a heme or cytochrome in oxygenation reactions between lanosterol and ergosterol.

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SynopsisThe fist confirmed synthesis of methylene malonamide (MeMal) is reported. This monomer was prepared by the thermal elimination or fluoride-ion-initiated elimination of trimethylsilyl chloride from a-chloro-a(trimethylsily1-2-methyl) malonamide. Spectral data for the monomer are given. MeMal has been shown to be unstable in a variety of protic organic solvents, including water and alcohols, thus giving the appropriate (a-methyl) substituted malonamides. MeMal is stable in most aprotic solvents.