Die Borierung von Lactamen und Harnstoffen mit einem Amino‐imino‐boran

• Published in: Chemische Berichte
• Main Authors: Geisberger, Gilbert, Neukirchinger, Katharina, Nöth, Heinrich
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1990
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/cber.19901230307; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fcber.19901230307; https://onlinelibrary.wiley.com/doi/pdf/10.1002/cber.19901230307

Contribution to the Chemistry of Boron, 201. ‐ Boration of Lactams and Ureas by an Amino‐Imino‐Borane Pyrrolidon reacts with ( tert ‐butylimino)(2,2,6,6‐tetramethylpiperidino)borane ( 1 ) to give the N ‐borated lactam 2 . Diketopiperazine behaves similarly. It is borated on both of its N atoms to form 3 . Urea and 1 give access to the O,N,N ′‐triborated isourea derivative 4 , which contains the structural unit of a ketiminoborane. The diborated carbodiimide 10 is ultimately obtained from 1 and thiourea via the triborated isothiourea derivative 9 . MNDO calculations have been used to estimate the relative thermodynamic stabilities of O/N borotropes of carbonic acid amides and lactams. They demonstrate that the O isomers gain in stability by increasing the size of N substituents.