tert-Butyldiphenylsilylhydrazine - Precursors for tetra(silyl)hydrazines, silylhydrazones, and O-silylpyrazolones

tert-Butylchlorodiphenylsilane reacts with hydrazine in presence of triethy lamine to give the mono(silyl)hydrazine Me3CSiPh2NHNH2 (1). The lithium der ivative of 1 (la) forms the N,N'-bis(silyl)hydrazines 2 and 3 in the reacti on with chlorosilanes. (2: Me3CSiPh2NHNHSiPh2CMe3; 3: Me3CSiPh2NHNHSiMe2CMe 3). The monomeric dilithium-hydrazide 4, (Me3CSiPh2)(2)N2Li2(THF)(3), is ob tained from 2 and the bimolar amount of C4H9Li in THF. 4 reacts with an exc ess of SiF4 to give the tetra(silyl)hydrazine 5, Me3CSiPh2(SiF3)N-N(SiF3)Si Ph2CMe3. 1 and ketones undergo condensation to silylhydrazones, Me3CSiPh2NH N=C(Me)R (6: R = Me; 7: R = CMe3), with elimination of H2O. Only one of the two possible isomers of 7 is formed. Cis/trans isomers (8 a, b) are obtain ed in the analogous reaction of 1 and ethyl acetoacetate, Me3CSiPh2NH-N=CMe -CH2-COOEt (8 a,b). 8 condenses thermally with elimination of EtOH and form ation of the O-silylpyrazolone 9, Me3CSiPh2O-(C=N-NH-CMe=CH-). The results of the crystal structure analysis of the compounds 2, 4, and 7 are reported .