Abstract N-Trimethylsilylamides react with aminohalogenoboranes in nearly quantitative yield to monomeric amido (bis) aminoboranes. From the reaction of N-substituted acylamides with bis (amino) halogenoboranes and dialkoxyhalogenoboranes respectively and triethylamine corresponding amido-bis (amino)-and amido-bis (alkoxy) boranes were obtained in high yields. In certain cases equilibria between monomeric and dimeric forms ...