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During the investigation of biologically active boron compounds in this laboratory, compounds such as 2-aminoacetic diphenylborinic anhydride were formed by heating butyl diphenylborinate with glycine.(C,H5)2BOC4H9 + H2NCH2COOH -0 (CeH6)2BO(ÜcH2NH2 + C4H"OHThe low-molecular weight amino acids, such as glycine, react well without a solvent. A solvent, such as toluene, is more convenient with the higher molecular weight, more soluble amino acids. The white solid products appear to be stable and have not undergone change on storage in air for 4 years. These anhydrides may be recrystallized from alcohol-water without change, but they react readily with ethanolamine to form 2-aminoethyl diphenylborinate. ExperimentalAll melting points were obtained on a Fischer-Johns melting point apparatus and were corrected by comparison with standard compounds.Reaction with Glycine.-A mixture of 0.50 g. (0.0067 mole) of glycine and 1.59 g. (0.0067 mole) of butyl diphenylborinate3 was boiled and stirred for 5 min. The mixture became solid.Toluene (5 ml.) was added, and the mixture was boiled for a few minutes. After cooling, the solid was collected on a filter and was washed with ether. The anhydride was boiled with 25 ml. of distilled water and was collected on a filter after cooling, 0.82 g., m.p. 244-245°, 51% (based on butyl diphenylborinate). A 0.33-g. portion was dissolved in 5 ml. of 95% ethanol, filtered while hot, cooled, and recrystallized once more from ethanol to yield 0.13 g., m.p. 244-245°.

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