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

Abstract

Contribution to the Chemistry of Boron, 2011). -Boration of Lactams and Ureas by an Amino-Imino-BoranePyrrolidon 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 Reaktionen rnit LactamenIn Hexan reagiert 2-Pyrrolidon rasch rnit 1 im Molverhaltnis 1 : 1 nach G1. (1) zum Amido-bis(amino)-boran 2.Hinweise auf die Bildung des 0-Isomeren fanden sich nicht. Gleiches gilt fur die sehr langsam ablaufende Umsetzung mit 2,5-Diketopiperazin, die ausschlieI3lich zu 3 fuhrt. Grund hierfiir diirften die heterogenen Reaktionsbedingungen sein. Reaktionen rnit Harnstoff und ThioharnstoffObwohl Harnstoff in Hexan praktisch unloslich ist, setzt er sich relativ schnell rnit 1 nach G1. (2)

B/C/N Materials and B4C Synthesized by a Non-Oxide Sol−Gel Process

“…The FT-IR and Raman spectra of the B/C/N xerogel clearly indicate the presence of NdCdN units showing characteristic asymmetric and symmetric CdN stretching modes around 2200 and 1600 cm -1 , respectively (Figure 1). 27 The positions of these signals agree well with the data of molecular borylated carbodiimides of the type: 28,29,30 Besides, the typical absorptions for N-H groups are found at 3440 cm -1 as expected because of the hydrogen- terminated borazene rings. An IR absorption band at 2964 cm -1 and the corresponding Raman emission maxima at 2964 and 2900 cm -1 show that residual Si-CH 3 groups are present.…”

First B-Organyloxy-Substituted Iminoboranes: Preparation, Stabilization, and Reactivity

“…A wide variety of reactions have been described both for iminoboranes and amino(imino)boranes; the extraordinary potential of these compound classes for synthetic purposes has thus been established. ,,− However, the number of reaction types that can possibly be carried out with our organyloxy(imino)boranes is severely limited, mainly by the fact that the unsaturated species can only be handled (for a relatively short period of time) in the solution in which it was formed. A potential reaction partner for an organyloxy(imino)borane would therefore have to meet at least the following requirements:…”