Preparation of N,N,N'-tris(trimethylsilyl)amidines; a convenient route to unsubstituted amidines

Article abstract of DOI:10.1016/0022-328X(87)80017-7

The tris(trimethylsilyl)amidines RC(NSiMe3)N(SiMe3)2 (R = C6H5, p-CH3C6H4, p-ClC6H4, p-MeOC6H4, p-Me2NC6H4, p-CF3C6H4, p-C6H5C6H4 and CF3) are prepared by the reaction of the respective nitriles with (Me3Si)2NLI.OEt2 in ether to give intermediates RC(NLi)N(SiMe3)2.Heating these intermediates with ClSiMe3 in toluene affords the products, which are isolated by vacuum distillation, in high yield.With 1,4-dicyanobenzene, two equivalents of reagents affords the per(trimethylsilyl)-1,4-diamidine.Hydrolysis of the intermediates with 6N ethanolic HCl affords the unsubstituted amidine hydrochlorides RC(NH)NH2.HCl (R = C6H5, p-MeOC6H4, p-ClC65H4, p-O2NC6H4) in high yield.