Azomethine derivatives. Part V. Reactions between organolithium compounds and diphenylketimine, some cyanides, and NNN′N′-tetramethylguanidine

Abstract

Reactions in ether between methyl-lithium and diphenylketimine, or between phenyl-lithium and phenyl cyanide, give a red solution of diphenylketiminolithium, Ph₂C:NLi, from which unsolvated (Ph₂C:NLi)_n may be obtained as a yellow amorphous and presumably polymeric solid, m. p. 260°(decomp.). Diphenylketiminolithium forms the coloured crystalline adducts Ph₂C:NLi,py, m. p. 108–110°(red) and Ph₂C:NLi, tetrahydrofuran, m. p. 127°(orange) which dissociate in benzene and deposit (Ph₂C:NLi)_n. Phenyl cyanide and methyl-lithium give yellow amorphous (PhCMe:NLi)_n, m. p. 196°. t-Butyl cyanide does not react with methyl-or ethyl-lithium at or below 20°, but methyl and ethyl cyanides with these alkyl-lithium compounds cleave alkane to give amorphous insoluble highly reactive solids believed to contain CCN– groups. A similarly reactive and apparently polymeric, insoluble solid results when dimethylcyanamide and methyl-lithium react and evolve methane. NNN′N′-Tetramethylguanidine and methyl-lithium give methane and the crystalline derivative [(Me₂N)₂C:NLi]₂ which is dimeric in benzene (by cryoscopy) and is also soluble in ether and toluene.