Boron‐nitrogen compounds. 94. Reactions of Dimethylaminoboranes with Pyrazole

Abstract

AbstractDepending on the reaction conditions, the interaction of tris(dimethylamino)borane with pyrazole (Hpz) yields (CH3)2HNBpz3 (III) or the pyrazaboles B2pz4[N(CH3)2]2 (IV, cis and trans isomer), B2pz5N(CH3)2 (Va), or B2pz6. There is evidence that the reactions proceed via the extremely short‐lived [(CH3)2N]2 Bpz and, in particular, monomeric (CH3)2NBpz2; the latter species can be identified in the mass spectrometer. In the system bis(dimethylamino)phenylborane/pyrazole the species (CH3)2HNB(C6H5)pz2 and the pyrazabole B2pz3(C6H5)2N(CH3)2 (VII, cis and trans isomer) were obtained. Also, some data on the pyrazabole B2pz2(C6H5)2[N(CH3)2]2 were collected although the compound could not be isolated in the pure state. The existence of the monomer (CH3)2NB(C6H5)pz could be established.